Two car bombs have exploded in a pro-government neighbourhood in the central Syrian city of Homs, killing at least 40 people hours after mortar strikes in the heart of the capital Damascus killed 14, officials said.
State news agency Sana said the attack in Homs struck in the Abbasiyeh neighborhood - a predominantly Christian and Alawite area. It said at least 40 people were killed and another 116 wounded.
The Britain-based Syrian Observatory for Human Rights put the death toll from the double car bombing at 37, including five children. It said more than 80 were wounded.
Such discrepancies in casualty figures are common in Syria in the immediate aftermath of attacks.
Homs has been an opposition stronghold since the uprising against Assad erupted in March 2011. Syria's third largest city has been the scene of some of the fiercest fighting in the civil war that followed the initially peaceful revolt.
A devastating government siege has squeezed rebels in the last outpost in the Old City, and the remaining fighters there have lashed back with suicide car bombings in pro-Assad areas.
In Damascus, several mortar shells slammed into the predominantly Shiite neighborhood of Shaghour, killing 14 people and wounding 86, Sana and state TV reported. The Observatory said 17 people were killed.
No one immediately claimed responsibility for the attacks, which came a day after president Bashar Assad declared his candidacy for the June 3 presidential elections, a race he is likely to win. Such attacks are common in Homs and Damascus, and there was no immediate indication that the violence was directly related to Assad's announcement.
Rebels fighting to oust him from power have frequently fired mortars into the capital from opposition-held suburbs, many of which have been under a crippling government blockade for months, with no food and medicine allowed to reach trapped civilians inside.
Armed opposition groups have also attacked Syria's cities with car bombs in the past months. An al Qaida-linked group has previously claimed several car bombings in the capital and other cities.
Sana blamed the attacks on terrorists - a term used by Assad's government for rebels.
Meanwhile, four more presidential hopefuls declared their candidacy in Syria's June 3 presidential election, bringing the total number of registered contenders to 11, state TV said.
Syria's opposition and its Western backers have criticised the decision to hold polling while the country is engulfed in fighting.
Syria's foreign ministry rejected the criticism, saying the decision was "sovereign" and warned that "no foreign power will be allowed to intervene".