BEIRUT – Syrian government forces stepped up their attack against rebel strongholds north of the capital Damascus on Saturday, while opposition fighters declared their own offensive in the country’s largest city, Aleppo.

Both sides intensified operations as an 11-nation group that includes the U.S., dubbed the Friends of Syria, began meeting in Qatar to discuss how to coordinate military and other aid to the rebels seeking to oust Syrian President Bashar Assad.

Friends of Syria agreed on Saturday to do more to help the embattled rebels trying to overthrow Assad, U.S. Secretary of State John Kerry said. While he offered no specifics about stepped-up military and humanitarian aid, Kerry said the assistance would help change the balance on the battlefield.

Kerry also denounced Assad for inviting Iranian and Hezbollah fighters to fight alongside his troops, saying the Syrian president risked turning the civil war into a regional sectarian conflict.

The fighting in Damascus came as the Syrian government announced salary increases to state employees and members of the military, days after the Syrian currency dipped to a record low of 210 pounds to the dollar compared with 47 when the crisis began more than two years ago.

The Britain-based Syrian Observatory for Human Rights, which relies on an extensive network of activists in Syria, said the shelling of the district of Qaboun has killed three children, including two from the same family, since Friday.

Activists reported heavy shelling on many fronts on districts north of Damascus, apparently an attempt to cut links between rebel-held districts that have served as launching pads for operations against the capital.

The Lebanese TV station Al-Mayadeen, which had a reporter embedded with Syrian government forces in the offensive, quoted a military official as saying that the operation aims to cut rebel supply lines, separate one group from another, and secure the northern entrances to the capital. The regime’s forces have struggled for months to regain control of these suburbs.

A recent declaration by the U.S. that it had conclusive evidence that President Bashar Assad’s regime used chemical weapons on a small scale against opposition forces prompted Washington to authorize the arming of rebels, a major shift in policy. The decision also followed advances by the government forces aided by fighters from Lebanon’s Hezbollah.

Rebels say they have already received new weapons from allied countries — but not the U.S. Experts and activists said the new weapons include anti-tank missiles and small quantities of anti-aircraft missiles.