Rebels entrenched in an eastern suburb of Damascus fired volleys of mortar shells that slammed into neighborhoods of the Syrian capital on Sunday, killing one child and wounding at least three people, Syria's state-run news agency and residents said.
The suburb known as Eastern Ghouta is held by rebels fighting to topple President Bashar Assad. The fighters often launch mortars into Damascus, Assad's seat of power.
Sunday's barrage was particularly strong and sustained, shaking residents out of bed in the early morning as shells struck residential districts.
SANA said a child was killed and three people wounded, and said the shells caused material damage to cars and buildings.
The government responded with airstrikes and missiles on suspected rebel outposts in Eastern Ghouta.
Opposition activists said at least 13 people were killed in Douma and Saqba, which are part of the same sprawling suburb.
The shelling came as the United Nations humanitarian chief, Stephen O'Brien, was visiting Damascus to review humanitarian work and assess the impact on civilians of the intensified fighting and military operations.
Following a meeting with Foreign Minister Walid al-Moallem, O'Brien said he was pursuing efforts to have humanitarian aid reach all Syrian people. Al-Moallem, according to SANA, emphasized the need for reconciliation and local truces to help in that regard.
More than 250,000 people have been killed and millions displaced in Syria's nearly five-year old conflict, which has left the country divided and devastated.
Islamic extremists control roughly half the country, including the Islamic State group and its rival, the al-Qaida branch in Syria known as the Nusra Front.
Nusra Front leader Abu Mohammad al-Golani said in rare comments aired late Saturday that local truces between the Syrian government and rebels only benefit the government. He criticized last week's deal in the Homs neighborhood of Waer, which saw a few hundred insurgents pull out of the district in return for a cease-fire and the delivery of humanitarian aid. Nusra Front fighters and other hardcore rebels were among those who evacuated Waer after rejecting the cease-fire deal.
"Truces are the first step to surrender," al-Golani said, speaking to a small group of local and loyalist journalists that was aired on the opposition Orient TV.
He also criticized as "unacceptable" a meeting of opposition factions held this week in Riyadh, Saudi Arabia, during which a framework for taking part in proposed peace negotiations with the government was reached.
He claimed the international community's goal is to incorporate the armed opposition with the government forces, keeping Assad as president, as a prelude to fighting extremist factions.
(Associated Press writer Zeina Karam in Beirut contributed to this report.)