A car bomb in Syria's northern city of Aleppo killed 12 government soldiers on Sunday while another powerful blast rattled the capital Damascus, killing at least three people, activists said.
The explosion in the capital went off behind a bakery in the Ruken al-Deen neighbourhood, according to the Britain-based Syrian Observatory for Human Rights. It reported 10 people were wounded and said there was no immediate claim of responsibility. The Syrian news agency SANA confirmed the blast and said there were casualties but did not give a number.
The Syrian army has been on the offensive against rebels in districts outside Damascus that are used as launching pads to attack the capital, President Bashar Assad's seat of power. Troop movements and heavy shelling on Saturday appeared to be an attempt to cut links between rebel-held districts there.
Elsewhere, the Observatory said 12 soldiers loyal to Assad were killed in a car explosion in the suburbs of the northern city of Aleppo, Syria's commercial capital.
It provided no other details, but both the government and the opposition have recently declared offensives in Aleppo.
The attacks coincided with a meeting of an 11-nation group that includes the US, dubbed the Friends of Syria, in the Qatari capital of Doha to co-ordinate military aid and other forms of assistance to the rebels.
Late on Saturday, the donors agreed to do more to help the embattled rebels, US Secretary of State John Kerry said. While he offered no specifics, Mr Kerry said the assistance would help change the balance on the battlefield.
Mr 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.
Syria's al-Thawra newspaper, the mouthpiece of the government, assailed the Friends of Syria meeting for providing aid to the rebels.
"It's clear that the enemies of Syria are rushing to arm the terrorists to kill the chances for holding the Geneva conference," the newspaper said, referring to a gathering planned to bring Assad's government to negotiate an end to the crisis with the fighting rebels.
It pledged that the Syrian army would "continue the showdown to eliminate terrorism and restore security and stability".