Syria special: The fall of Babr Amr

Thousands of Syrian civilians were abandoned to their fate on Thursday when government troops captured the principal rebel stronghold in the city of Homs.

The 4th division, controlled by President Bashar al-Assad's younger brother, Maher, claimed to have seized the district of Baba Amr after 26 days of bombardment.

Opposition activists feared a campaign of retribution against the 4,000 civilians thought to be inside Baba Amr. Tens of thousands living in districts nearby were also thought to be vulnerable.

Baba Amr has had no electricity and little food or medicine since the offensive began and freezing weather has worsened conditions. Some of the rare video footage to emerge from the area, where communication links were all but severed, showed residents crouching on a road as they tried to collect falling snow in buckets to serve as drinking water.

The regime's apparent military victory coincided with a sign that its key allies, Russia and China, were no longer willing to offer unconditional support. The United Nations Security Council passed a unanimous statement last night urging Syria to allow Baroness Amos, the UN's humanitarian affairs chief, to visit Syria to negotiate free access for aid agencies.

Russia and China, which vetoed a draft resolution last month that would have urged Mr Assad to step down, both supported this statement.

A daily ceasefire lasting two hours is needed to allow the delivery of humanitarian supplies to areas torn by fighting, according to the International Committee of the Red Cross. Yesterday, an ICRC spokesman said the organisation had received "positive indicators from the Syrian authorities" that this demand would be accepted.

Any such move could come too late for the residents of Baba Amr. Most of the 7,000 pro-regime forces that marched into the largely Sunni district were members of Mr Assad's Alawite minority, a sect of Shia Islam. They have already been accused of atrocities against the Sunni majority, from whose ranks the opposition is largely drawn.

Residents who fled Homs said that soldiers were going from house to house in some suburbs, arresting every man over the age of 15 and under the age of 65. There was no word on the whereabouts of two French reporters, Edith Bouvier and William Daniels, who have been trapped in Baba Amr since the attack that killed Marie Colvin and Remi Ochlik, on February 22. One of Miss Bouvier's legs was broken in the incident.

The rebel Free Syrian Army sought to put a positive gloss on the retreat of its Farouq and Khalid bin Walid battalions from Homs. "There has been a tactical withdrawal," Riad al-Assad, the group's commander, told Al Jazeera television. "The Free Army has left Baba Amr because of the brutal acts of the regime against civilians."

One fighter, however, conceded that the rebels had effectively been beaten. "We were running out of ammunition and we were completely outnumbered," he said, speaking on condition of anonymity. "But we will return to fight again soon. Assad will see that he can defeat us but he cannot conquer us."

While Mr Assad may believe he has turned the tide of the uprising, it is not the first time the rebels have been forced to flee Baba Amr. They last withdrew after being defeated in November, but were able to return as government forces were deployed to counter unrest elsewhere in the country. Previous experience suggests that, although Mr Assad retains the upper hand thanks to the loyalty of the Alawite-dominated officer ranks, he does not have enough reliable soldiers to defeat the rebels completely.

Even so, the insurgents were thought to have suffered heavier losses than during the latest offensive in Homs. There were fears that infighting and the lack of a proper command structure were hampering the FSA's ability to challenge the government.

Burhan Ghalioun, leader of the Syrian National Council, an umbrella organisation of civilian opposition groups, announced that he had formed a military bureau to oversee and organise anti-Assad soldiers. By doing so, he effectively ended efforts to keep the civilian opposition distinct from rebel fighters, who initially took up arms to protect street demonstrations, but are now fighting a classic insurgency.

"The revolution started peacefully and kept up its peaceful nature for months," Mr Ghalioun said. "But the reality today is different and the SNC must shoulder its responsibilities in the face of this new reality."