Beirut ? After a punishing, monthlong military siege, Syrian rebels made what they called a “tactical retreat” Thursday from a key district in Homs, saying they were running low on weapons and the humanitarian conditions were unbearable.

Within hours of the rebels’ withdrawal, President Bashar Assad’s regime granted permission for the International Committee of the Red Cross to enter the neighborhood of Baba Amr, which had become a symbol of the resistance.

Human rights workers have been appealing for access for weeks to deliver food, water and medicine, and to help evacuate the wounded from an area that has been sealed off and attacked by the government since early February.

The Red Cross and the Syrian Arab Red Crescent received a “green light” from the Syrian authorities to enter Baba Amr on Friday “to bring in much-needed assistance including food and medical aid, and to carry out evacuation operations,” ICRC spokesman Hicham Hassan told The Associated Press in Geneva.

Also Thursday, Syria’s main opposition group, the Syrian National Council, formed a military bureau to help organize the armed resistance and funnel weapons to rebels — a sign of how deeply militarized the conflict has become over the past year.

The uprising began in March 2011 with mostly peaceful protests, but a fierce government crackdown has led many army defectors and others to take up arms and fight back, with more than 7,500 estimated killed. The siege of Baba Amr has been among the deadliest assaults as Syrian forces bombarded the district with shells and snipers fired from rooftops.

Late Thursday, a Syrian official said the army had entered and taken control of the area.

The Local Coordination Committees said there were 45 deaths recorded in Syria Thursday, 24 of them in Homs.

Hundreds of people were killed and an unknown number wounded in Baba Amr; bloodied victims were forced to seek help in makeshift clinics with dwindling supplies amid a frigid winter.