BEIRUT — Syrian rebels clashed with regime troops in the narrow stone alleyways around a historic 12th century mosque inside the walled Old City of Aleppo on Thursday, while a government airstrike in the countryside north of the city killed at least seven people, activists said.

The rebels, who have been slowly chipping away at the regime’s hold on Aleppo, received a boost Wednesday from the U.S. in their fight to oust Syrian President Bashar Assad. Washington pledged an additional $60 million in assistance to the opposition and — in a significant policy shift — for the first time will provide nonlethal aid like food and medical supplies directly to rebel forces on the ground.

U.S. Secretary of State John Kerry announced the decision on the sidelines of an international conference on Syria in Rome, where European nations were also expected to signal their intention to provide fresh assistance to the opposition, possibly including defensive military hardware.

The rebels have made a number of strategic gains in northern Syria in recent weeks, including the capture of a hydroelectric dam and some military bases. They also have been regularly hitting the heart of Damascus with mortar rounds, puncturing the aura of normalcy that the regime has tried to cultivate in the capital.

In Aleppo, a key battleground in the civil war, clashes raged around the landmark Umayyad Mosque in the walled Old City, the Britain-based Syrian Observatory for Human Rights said. The rebels control one part of the mosque, and government troops hold the other.

Rebels launched an offensive on Aleppo, Syria’s largest urban center and its commercial capital, in July 2012. Since then, the city has been carved into rebel- and government-controlled zones in brutal street fighting that has destroyed entire neighborhoods and damaged some of the ancient city’s rich archaeological and cultural heritage.

The Umayyad Mosque, also known as the Great Mosque of Aleppo, sits near a medieval covered market in the Old City, which is a UNESCO World Heritage site. The mosque was heavily damaged in October 2012 just weeks after a fire gutted the old city’s famed market.

North of Aleppo, a government airstrike on the village of Deir Jamal killed at least seven people, including five children, according to the Observatory. It was not immediately clear what the target was, but regime warplanes frequently carry out bombing runs on rebel-held towns.

Farther south in the central city of Homs, the state news agency said a car bomb caused casualties and extensive material damage, but it did not elaborate.

An official in the Homs governor’s office told The Associated Press that there were two blasts and that four people were killed and at least six wounded. The official spoke on condition of anonymity in line with regulations.

With the bloodshed showing no sign of abating, the Syrian opposition has grown increasingly frustrated with what it sees as the international community’s apathy toward the suffering on the ground and its unwillingness to provide rebels with the arms they need to counter the regime’s superior firepower.

The U.S. and its European allies have been reluctant to arm the opposition fighters the ground for fear the weapons could end up in the hands of Islamic militants, who might then carry out attacks on Western or Israeli targets.

So far, the U.S. has largely limited its assistance to the Syrian opposition to funding for communications and other logistical equipment.

The U.S. decision to provide more aid directly to the rebels is designed to increase the pressure on Assad to step down and pave the way for a democratic transition. The aid is also intended to help the opposition Syrian National Coalition govern newly liberated areas of Syria and blunt the influence of extremists.

“For more than a year, the United States and our partners have called on Assad to heed the voice of the Syrian people and to halt his war machine,” Kerry said in Rome. “Instead, what we have seen is his brutality increase.”

The Coalition, which has been hampered by the same infighting that has dogged the opposition since the uprising began, has struggled to agree on the leadership of a transitional administration since the opposition umbrella group was formed late last year. The group has met on previous occasions to select an interim prime minister, but has failed to reach a compromise.

In a statement posted on its Facebook page, the group said the March 2 conference in Istanbul was canceled for “logistical reasons.” It said it would announce a new date as soon as possible.

Walid al-Bunni, a spokesman for the Coalition, said the meeting was pushed back “for few days” to allow for more consultations with members of the opposition inside Syria who have been hampered by security issues and because some local councils who were supposed to take part in the conference were holding elections.