UN humanitarian chief Valerie Amos has entered the ruins of the devestated Baba Amr district of Homs with the Syrian Red Crescent aid agency.
Amos is in Syria to assess the humanitarian needs of civilians who have suffered under weeks of intense government shelling attacks.
The International Committee of the Red Cross (ICRC) said that Amos spent about an hour with the Red Crescent in the devestated area of Homs before moving on to other parts of the city.
Her visit precedes that of UN and Arab League special envoy Kofi Annan, who will arrive in the country for his own meetings with government officials and aid agencies on 10 March.
Relief workers have been waiting for almost a week for access to Baba Amr, but have been blocked by government security forces citing unexploded shells as the reason for the delay.
According to the BBC despite the visit to Baba Amr the Red Crescent has not been able to distribute aid in the district.
The ICRC said that most residents of Baba Amr had now left for other areas of the city or had left Homs entirely.
It was reported yesterday that refugees fleeing from Homs to the Lebanese border in the south west had been attacked by security forces.
Activists said that there were fears the regime could now turn its attention on Al Khalidiya, another anti-Assad neighbourhood.
Avaaz said that more reinforcements were entering Homs and that government aircraft had been spotted in the sky above the city.
One activist known as 'Bilal' said that shells had been destroyed houses in the Jeb Jandali and Bab Tadmor neighbourhoods.