Baba Amr

(CNN) -- Aid groups got the green light to enter the besieged Syrian enclave of Baba Amr as government forces moved in Thursday to take control of the restive anti-regime enclave.

Security forces barged into homes and snipers took positions on the rooftops of government buildings after opposition forces retreated, activists said.

The army "entered Baba Amr today in full force" amid what one activist source called a "bloodbath" in the neighborhood, which has been shelled relentlessly for more than three weeks, said Avaaz, an anti-government activist group.

"There are bodies on the street. Residents have never been more desperate. There is no food, no medicine and civilians are melting snow for drinking water," said Alice Jay, an Avaaz official.

The forces effectively ignored an overwhelmingly backed U.N. Human Rights Council resolution on Thursday that condemned Syria's "widespread and systematic violations of human rights" and called on the regime to permit aid groups in to distribute relief.

One of the places in need is Baba Amr, one of several pockets of anti-regime resistance in the city and across Syria. Resistance fighters have fought back and most civilians have stayed put. Activists said explosions could be heard Thursday after the Free Syrian Army retreated.

The advance was made as the FSA, the anti-government resistance force, on Thursday said it had decided to strategically withdraw for the sake of the civilians remaining inside the neighborhood, citing dismal humanitarian conditions and a lack of arms to defend civilians.

It said around 4,000 civilians were refusing to leave the neighborhood.

"There is no food whatsoever, no medicines, no water and no electricity. There is no communication in the area, thus making matters much worse," it said. "The Assad army has destroyed most of the civilian homes up to now" using missiles, mortar shells and helicopters.

As the FSA, Avaaz and other groups urged international humanitarian aid for Homs, authorities have permitted the International Committee of the Red Cross and the Syrian Red Crescent to bring relief to Baba Amr.

ICRC spokeswoman Carla Haddad Mardini said the government is permitting humanitarian workers to deliver of food and medical supplies to Baba Amr and to carry out evacuation operations starting Friday. She said the operation will be complex because it is snowing in the city.

Also, the U.N. Security Council called on Syrian authorities to grant Valerie Amos, the U.N. under secretary -general for humanitarian affairs and the emergency relief coordinator, "immediate and unhindered access" to Syria.

British Ambassador to the U.N. Mark Lyall Grant said Amos had not been granted authorization to visit Syria "in a timely manner, despite repeated requests and intense diplomatic contacts aimed at securing Syrian approval."

A spokesman for Syria's Foreign and Expatriates Ministry said it didn't reject her visit, but it said they were "surprised about her having arrived in the region and asking to come to Syria on a date not suitable for us."

"The Syrian side is ready to continue consultation with Amos on a date that is appropriate for both sides," the spokesman said, according to the state-run Syrian Arab News Agency.

The Local Coordination Committees of Syria, an opposition activist group, said at least 40 people had died in Syria on Thursday -- 23 in Homs, seven in the Quneitra province town of Jabata, and others in the Damascus suburbs, the Hama suburbs, Daraa and Idlib.

CNN cannot independently confirm casualty reports by the opposition, activists or the Syrian government because access to the country by international journalists has been severely restricted.

Avaaz said 17 civilians were beheaded or partially beheaded in a farming area on the outskirts of Baba Amr. Avaaz said it has verified all 17 names.

"A key FSA source from inside the district told Avaaz 'hundreds of bodies' of the dead and injured were lying in the rubble of shelled houses and in the street. He added that women and children attempting to flee Baba Amr to neighboring Sultaniya last night were trapped by regime shelling, and many were killed," Avaaz said.

Dima Moussa, spokeswoman of the Revolutionary Council of Homs, said conclusions about the conditions in Homs are "still for the most part speculative" because of communications problems.

"What we know is that Free Syrian Army soldiers who were in Baba Amr have withdrawn in an attempt to protect the civilians from further attacks and violence by the Assad forces, which had escalated their offense against the neighborhood," Moussa told CNN. "A ground attack was going to surely result in more civilian casualties, and therefore, the FSA soldiers withdrew to continue their work, where their number one concern is protecting the civilians.

"Nevertheless, the Assad forces carried out a raid-and-arrest campaign in the neighborhood, where they went in and started randomly raiding civilians' homes and arresting them, or whatever is left of them in the neighborhood," she said.

Syria's violent crackdown against protesters rallying to redress a range of political and social grievances erupted in mid-March.

The United Nations estimates 7,500 deaths and the Local Coordination Committees, an opposition activist group, said around 9.000 people have died in the nearly year-old conflict. The Syrian government says more than 2,000 security personnel have been killed in the violence.

Thirty-seven of the nations in the Human Rights Council meeting in Geneva, Switzerland, voted for the resolution, including the United States and several Arab countries. China, Russia and Cuba opposed it and India, the Philippines and Ecuador abstained.

"The international community sends yet another unequivocal call to the Syrian authorities to stop human rights violations against its population and to address urgent humanitarian needs," said the European Union's foreign policy chief, Catherine Ashton. "The situation in Syria must remain at the center of the world's attention and every possible lever must be pulled to stop the violence and the killing of civilians."

The resolution deplores "the brutal actions of the Syrian regime over the past 11 months, such as its use of heavy artillery and tanks to attack residential areas of cities and towns, which have led to the death of thousands of innocents civilians, caused widespread destruction, forced tens of thousands of Syrians to flee their homes and created widespread suffering among the Syrian people, resulting in a humanitarian crisis."
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It calls for "the effective delivery of assistance" and "safe access to medical treatment." It wants "free and unimpeded access by the United Nations and humanitarian agencies to carry out a full assessment of needs in Homs and other areas, and to permit humanitarian agencies to deliver vital relief goods and services" to Homs, Daraa, Zabadani and other areas that have been under siege.

The Human Rights Council's move punctuates the growing international consensus against the al-Assad regime and its policies. On Friday, international powers met in Tunisia for a Friends of Syria meeting to begin working on ways to stop the violence, devise a political solution, and deliver aid. That group formed last month after Russia and China vetoed a U.N. Security Council resolution condemning the Syrian government.

The Friends of Syria meeting last week underscored the importance of the political opposition movement, including the Syrian National Council, but the group didn't make reference to armed conflict as a solution, even though a Saudi Arabian diplomat said arming rebels would be a very good idea.

The council announced Thursday it had established a "military bureau" to coordinate with the Free Syrian Army, or FSA, a decentralized network of military defectors resisting the al-Assad regime..

"The Military Bureau will track the armed opposition groups, organize and unify their ranks under one central command, defining their defense missions while placing them under the political supervision of the SNC, and coordinating their activities in accordance with the overall strategy of the revolution," the council said.

"The SNC will work on providing the FSA with all the support it needs to completely fulfill its defense responsibilities, including securing necessary protection for civilians, and tending to the revolutionaries defending Syrians against the criminal regime. Bureau members will seek assistance from appropriate sources, including experts."

The Free Syrian Army, which consists of many disparate militia groups operating under the FSA banner, has grown over the months and is made up primarily of former regime soldiers who refused to accept orders to fire on innocent protesters. The group's Baba Amr brigade on Thursday warned the al-Assad regime it would see a "severe response" to any regime actions that "crosses the limits and affects civilians."

Arab League Secretary-General Nabil Elaraby said Thursday the council and the rest of the opposition should unite.

"This is a matter that the Arab League has requested and we are in current talks with them. What we are thinking of now is that in a short period, maybe two weeks at the most, we would like to hold a conference in Cairo for all factions of the Syrian opposition so as to unite their efforts and coordinate their positions," he said.

In London, British Foreign Secretary William Hague told Parliament he was withdrawing diplomats from Syria and suspending embassy operations for security reasons.