BEIRUT (AP) — Syrian troops backed by airstrikes broke a yearlong rebel siege of a prison in the northern city of Aleppo Thursday, allowing President Bashar Assad’s forces to close in on a nearby command center of a coalition of Islamist rebel groups.

The sprawling prison has witnessed deadly clashes between government and opposition forces for the past year. Rebels repeatedly have barreled suicide car bombs into the front gates and fought guards and troops holed up inside, seeking to free an estimated 4,000 inmates.

Aleppo has been carved into rebel- and government-controlled areas since opposition fighters launched an offensive in Aleppo in mid-2012. The Syrian army has seized the momentum in the center of the country and is seeking to advance against opposition-held areas in the north ahead of the June presidential election.

Government forces began a final push on Tuesday and entered the prison at dawn Wednesday after rebels besieging the facility fled under intense aerial bombardment of explosives-packed barrels, according to Aleppo-based activists and the Britain-based Syrian Observatory for Human Rights.

The Observatory expressed fears that government forces might kill some of the inmates and “claim that they died during the rebels’ siege of the prison.”

Lebanon’s Al-Mayadeen and Al-Manar television stations, which are close to the Syrian government and have reporters in different parts of Syria, also reported that government troops ended the siege, which began in April 2013.

Aleppo Central Prison lies on a highway about six kilometers (four miles) north of the city of Aleppo, once Syria’s prized commercial center. The war devastated the city, leaving rebels controlling its east as Assad’s forces hold its west.

“The air raids were astonishing,” said Ibrahim Saeed, an activist based in Aleppo province. “The air force tipped the balance of power. More than 100 barrel bombs struck the area around the prison.”

Saeed said the next target of government forces appears to be the nearby town of Handarat, followed by the Kindi Hospital in an attempt to cut off rebel supply lines from the countryside into Aleppo.

He added that after the capture of the prison, Assad’s forces are now close to a command center of the Islamic Front alliance, a powerful coalition of seven rebel groups fighting the government. The center is in an army infantry base that was captured by rebels two years ago.

Activists say more than 160,000 people have been killed since the Syrian conflict started in March 2011 as largely peaceful protests against Assad’s rule that deteriorated into civil war. The fighting has also uprooted 9 million people from their homes, with over 6 million Syrians seeking shelter in safer parts of the country and at least 2.7 million fleeing to neighboring countries.

In Geneva, the International Committee of the Red Cross said it is working with the Syrian Arab Red Crescent to deliver food for over 60,000 people displaced by violence in opposition and government-held areas in Aleppo province.

“This assistance is the result of months of negotiations with various parties,” said Boris Michel, the head of the ICRC delegation in Syria. “The areas we reached in the last few days had not received any humanitarian aid for nine months. The needs are significant.”

The statement said a three-truck, joint ICRC and Syrian Arab Red Crescent convoy crossed front lines to bring food to over 30,000 people in the towns of Al Bab and Manbij, where thousands of displaced people have sought refuge in recent months. It said more food will be distributed in the coming days in other areas.

Copyright 2014 The Associated Press.