The leaders of the US, Britain, Germany and France have called on Syria's president to step down as international pressure mounts on the regime after months of violent crackdown against protesters.
US President Barack Obama said on Thursday that Bashar al-Assad was "standing in the way" of the Syrian people.
"For the sake of the Syrian people, the time has come for president Assad to step aside."
Hillary Clinton, the US Secretary of State, also said it was time for the Syrian leader to step down.
In a joint statement released shortly after, Angela Merkel, Nicolas Sarkozy and David Cameron said they called on Assad to step aside "in the best interests of Syria and the unity of its people".
"The Syrian authorities have ignored the urgent appeals made over recent days by the United Nations Security Council, by numerous States in the region, the Gulf Cooperation Council and by the Secretaries-General of the League of Arab States and of the Organisation of Islamic Cooperation," the statement said.
"They continue to cruelly and violently repress their people and flatly refuse to fulfil their legitimate aspirations. They have ignored the voices of the Syrian people and continuously misled them and the international community with empty promises."
The leaders added they are supporting further strong EU sanctions against the regime of president Assad.
Catherine Ashton, the European Union's foreign policy chief, reiterated the bloc's condemnation of the "brutal campaign" waged by Assad's regime against protesters and said the leader had lost legitimacy.
"The EU has repeatedly emphasised that the brutal repression must be stopped, detained protesters released, free access by international humanitarian and human rights organisations and media allowed, and a genuine and inclusive national dialogue launched," her statement said.
"The Syrian leadership, however, has remained defiant to calls from the EU as well as the broad international community including Syria's own neighbours. This shows that the Syrian regime is unwilling to change."
Stephen Harper, Canada's prime minister, also joined in on calls for Assad to step down immediately.
"The Syrian people have a right to decide for themselves the next steps for Syria's future,” he said.
The statements come after a report by UN Human Rights Commissioner Navi Pillay said the situation in Syria could amount to "crimes against humanity" and urged the Security Council to refer it to the International Criminal Court.
The report urged an immediate end to "the gross human rights violations, including the excessive use of force against demonstrators and the killing of protesters, torture and ill-treatment of detainees and enforced disappearance".
“Fadi” a citizen journalist for the human rights group Avaaz, said that attacks were still continuing in the city of Homs a day after Assad pledged the military campaign against protesters had ended.
“I'm hearing about of a lot of attacks and arresting, especially in the districts of Khaldiya and Al Sebaa.
"Although there are no tanks inside the city, there are tanks on the outskirts and in the rural areas. Army presence in the city is in the form of snipers scattered around on the roofs of tall buildings. We have a lot of photos and videos of them."
Wissam Tarif of Avaaz, said Clinton's statement was a "positive step in the right direction" but said Turkey must follow suit.
"Europe must go further and cut off Assad’s financial supply line of selling oil into Europe by introducing sanctions when they meet in Brussels tomorrow."