Dozens of people have been wounded in Thailand's capital, Bangkok, after an explosion ripped through an anti-government rally.

At least 28 people have been injured after a grenade was hurled at demonstrators marching through Bangkok at midday.

The blast is an ominous development that raises tensions in the country's political crisis and the spectre of more bloodshed to come.

In recent days, other low-power explosive devices have been thrown at the homes of the country's former opposition leader Abhisit Vejjajiva and his ally Sukhumbhand Paribatra, the governor of Bangkok.

Drive-by-shootings at various protest camps set up around Bangkok also have resulted in minor injuries, while clashes between demonstrators and police or pro-government sympathisers resulted in the deaths of eight people previously.

Army commander-in-chief Gen Prayuth Chan-ocha has expressed his concern that if the situation deteriorates then Thailand could be tipped into a low-intensity civil war.

Loading Slideshow...
  • Anti-government protesters march during a rally Friday, Jan. 17, 2014, in Bangkok, Thailand. Thailand's prime minister was facing fresh legal troubles Friday after the country's anti-corruption commission announced it would investigate her handling of a controversial rice policy. (AP Photo/Sakchai Lalit)

  • Anti-government People's Democratic Reform Committee (PDRC) protesters stand in an alleyway as they search dilapidated buildings for possible suspects near the scene of an explosion in the Pathumwan district, Friday, Jan. 17, 2014, in Bangkok. Dozens of people were wounded in the capital Friday when an explosion hit anti-government demonstrators marching through Bangkok in broad daylight, an ominous development that raises tensions in the country’s political crisis and the specter of more bloodshed to come. (AP Photo/John Minchillo)

  • An anti-government protester injured in an explosion is carried by her fellow protesters during a demonstration in Bangkok, Thailand, Friday, Jan. 17, 2014. Dozens of people were wounded when an explosion hit anti-government demonstrators marching through Bangkok in some of the bloodiest violence reported this year. (AP Photo/Astv Manager Newspaper) THAILAND OUT

  • An anti-government protester injured in an explosion is assisted by her fellow protesters during a demonstration in Bangkok, Thailand, Friday, Jan. 17, 2014. Dozens of people were wounded when an explosion hit anti-government demonstrators marching through Bangkok in some of the bloodiest violence reported this year. (AP Photo/Astv Manager Newspaper) THAILAND OUT

  • An anti-government protester injured in an explosion is carried by his fellow protesters during a demonstration in Bangkok, Thailand, Friday, Jan. 17, 2014. Dozens of people were wounded when an explosion hit anti-government demonstrators marching through Bangkok in some of the bloodiest violence reported this year. (AP Photo/Astv Manager Newspaper) THAILAND OUT

  • Anti-government protesters search an abandoned building for possible suspects near the scene of an explosion Friday, Jan. 17, 2014, in Bangkok, Thailand. Dozens of people were wounded in Thailand's capital Friday when a grenade was hurled at anti-government demonstrators marching through Bangkok at midday, an ominous development that raises tensions in the country's political crisis and the specter of more bloodshed to come. (AP Photo/Sakchai Lalit)

  • Blood splatters the pavement near the scene of an explosion that targeted an anti-government People's Democratic Reform Committee (PDRC) protest march in the Pathumwan district, Friday, Jan. 17, 2014, in Bangkok. Dozens of people were wounded in the capital Friday when an explosion hit anti-government demonstrators marching through Bangkok in broad daylight, an ominous development that raises tensions in the country’s political crisis and the specter of more bloodshed to come. (AP Photo/John Minchillo)

  • Anti-government People's Democratic Reform Committee (PDRC) demonstrators search of dilapidated buildings near the scene of an explosion that targeted a protest march in the Pathumwan district, Friday, Jan. 17, 2014, in Bangkok. Dozens of people were wounded in the capital Friday when an explosion hit anti-government demonstrators marching through Bangkok in broad daylight, an ominous development that raises tensions in the country’s political crisis and the specter of more bloodshed to come. (AP Photo/John Minchillo)

  • Anti-government People's Democratic Reform Committee (PDRC) demonstrator walk after an explosion that targeted a protest march in the Pathumwan district, Friday, Jan. 17, 2014, in Bangkok. Dozens of people were wounded in the capital Friday when an explosion hit anti-government demonstrators marching through Bangkok in broad daylight, an ominous development that raises tensions in the country’s political crisis and the specter of more bloodshed to come. (AP Photo/John Minchillo)

  • Anti-government protesters search an abandoned building for a bomber who threw an explosive device during a march by protest leader Suthep Thaugsuban and his supporters in downtown Bangkok, Thailand Friday, Jan. 17, 2014. Dozens of people were wounded in Thailand's capital Friday when an explosion hit anti-government demonstrators marching through Bangkok in some of the bloodiest violence reported this year. (AP Photo/Daily News) THAILAND OUT

  • An injured anti-government protester is carried by other protesters during a demonstration in Bangkok, Thailand, Friday, Jan. 17, 2014. Dozens of people were wounded in Thailand's capital Friday when a grenade was hurled at anti-government demonstrators marching through Bangkok at midday, an ominous development that raises tensions in the country's political crisis and the specter of more bloodshed to come. (AP Photo/Str)

  • Injured anti-government protesters are taken out from a street by other protesters during a demonstration in Bangkok, Thailand, Friday, Jan. 17, 2014. Dozens of people were wounded in Thailand's capital Friday when a grenade was hurled at anti-government demonstrators marching through Bangkok at midday, an ominous development that raises tensions in the country's political crisis and the specter of more bloodshed to come. (AP Photo/Str)

  • An injured anti-government protester is helped by his fellow protesters after he was hit by a bomb blast during the march with leader Suthep Thaugsuban in downtown Bangkok, Thailand Friday, Jan. 17, 2014. Dozens of people were wounded in Thailand's capital Friday when an explosion hit anti-government demonstrators marching through Bangkok in some of the bloodiest violence reported this year. (AP Photo/Daily News) THAILAND OUT

  • Anti-government People's Democratic Reform Committee (PDRC) demonstrator searches dilapidated buildings near the scene of an explosion that targeted a protest march in the Pathumwan district, Friday, Jan. 17, 2014, in Bangkok. Dozens of people were wounded in the capital Friday when an explosion hit anti-government demonstrators marching through Bangkok in broad daylight, an ominous development that raises tensions in the country’s political crisis and the specter of more bloodshed to come. (AP Photo/John Minchillo)

  • An anti-government People's Democratic Reform Committee (PDRC) demonstrator leans out of a broken wall during a search of dilapidated buildings near the scene of an explosion that targeted a protest march in the Pathumwan district, Friday, Jan. 17, 2014, in Bangkok. Dozens of people were wounded in the capital Friday when an explosion hit anti-government demonstrators marching through Bangkok in broad daylight, an ominous development that raises tensions in the country’s political crisis and the specter of more bloodshed to come. (AP Photo/John Minchillo)

  • Anti-government People's Democratic Reform Committee (PDRC) demonstrators are held at an opening in a steel wall as military units secure an area near the scene of an explosion that targeted a protest march in the Pathumwan district, Friday, Jan. 17, 2014, in Bangkok. Dozens of people were wounded in the capital Friday when an explosion hit anti-government demonstrators marching through Bangkok in broad daylight, an ominous development that raises tensions in the country’s political crisis and the specter of more bloodshed to come. (AP Photo/John Minchillo)

  • Anti-government protesters look out from windows while searching an abandoned building for possible suspects near the scene of an explosion Friday, Jan. 17, 2014, in Bangkok, Thailand. Dozens of people were wounded in Thailand's capital Friday when a grenade was hurled at anti-government demonstrators marching through Bangkok at midday, an ominous development that raises tensions in the country's political crisis and the specter of more bloodshed to come. (AP Photo/Sakchai Lalit)

  • An injured anti-government protester is helped in to an ambulance after he was hit by a bomb blast during a march with leader Suthep[ Thaugsuban in downtown Bangkok, Thailand Friday, Jan. 17, 2014. Dozens of people were wounded in Thailand's capital Friday when an explosion hit anti-government demonstrators marching through Bangkok in some of the bloodiest violence reported this year. (AP Photo/Daily News) THAILAND OUT

  • Suthep Thaugsuban

    People's Democratic Reform Committee (PDRC) leader Suthep Thaugsuban smiles while moving through an protest encampment after an explosion hit a march he was leading through the Pathumwan district, Friday, Jan. 17, 2014, in Bangkok. Dozens of people were wounded in the capital Friday when a grenade was hurled at anti-government demonstrators marching through Bangkok at midday, an ominous development that raises tensions in the country's political crisis and the specter of more bloodshed to come. Suthep was in the procession but was not wounded when the explosive device was thrown into a truck driven by demonstrators that was several dozen meters (yards) ahead, spokesman Akanat Promphan said. (AP Photo/John Minchillo)

  • Anti-government protesters injured in an explosion during a demonstration wait for doctors in Bangkok, Thailand, Friday, Jan. 17, 2014. Dozens of people were wounded when an explosion hit anti-government demonstrators marching through Bangkok in some of the bloodiest violence reported this year. Protest spokesman Akanat Promphan said an explosive device was thrown into a truck driven by demonstrators that was several dozen meters (yards) ahead of the movement leader Suthep Thaugsuban, who was not wounded in the blast. (AP Photo/Astv Manager Newspaper) THAILAND OUT