The overnight blast struck near a police station in the town of Deir Atiyeh, the UK-based Syrian Observatory for Human Rights said.
State-run Sana news agency confirmed the attack, saying “terrorists” had caused an unknown number of casualties.
The blast comes as the Syrian army tries to regain ground around Damascus.
Correspondents say the government looks poised to retake Jobar and advance towards Qaboun, both held for months by opposition forces.
Rebels have used Jobar and Qaboun to launch mortar rounds on government positions in the heart of the capital, reports say.
“The army is advancing rapidly in Jobar,” a Syrian military commander told the Associated Press.
“The area will be secured in the next few days according to a well-studied plan.”
The observatory – which relies on a network on opposition activists on the ground – said 200 civilians had been held captive by government troops inside a mosque in Qaboun on Sunday night.
They were able to escape when clashes broke out near the mosque and the army retreated, the observatory said. The report cannot be verified.
Meanwhile, fighting is said to have intensified in the city of Aleppo between jihadists and the main opposition forces the Free Syrian Army (FSA).
The clashes follow the assassination in Latakia of an FSA commander at the hands of a group linked to al-Qaeda.
The killing late last week is part of an escalating struggle within the armed uprising between moderates and Islamists.
In another development, the Pakistani Taliban told Reuters news agency on Sunday that they had sent “hundreds” of fighters to Syria.
A senior commander said they had gone at the request of “Arab friends” and had set up camps in Syria.
UN says more than 90,000 people have been killed in Syria since the uprising again President Bashar al-Assad began in 2011. A further 1.7 million have been forced to seek shelter in neighbouring countries. – BBC: Syria crisis: Deadly car bomb strikes north of Damascus
Shells hit Damascus as Syrian troops gain more ground in Homs
(English CN News) – A mortar shell hit a service center in al-Qaboun district in the Syrian capital of Damascus on Monday, injuring 24 people, while another mortar shell landed in neighboring Barzeh district, official SANA news agency said.
Al-Qaboun and Barzeh lie on the Eastern edge of the capital and border the suburban districts of Harastan, Duma and Jobar, where opposition militias still have an active presence.
Syrian Army on Sunday discovered a factory to manufacture and store toxic chemical weapons ran by the opposition, according to an army source. Among the seized material are containers with chlorine and mortar shells that could be filled with the substance.
The source also identified that some of the material were made in foreign countries, including Saudi Arabia.
In the meantime, the government troops maintained a steady pace in pushing the opposition out of the central city of Homs and rural Damascus, according to state media.
SANA said the army has made advances in a dozen of neighborhoods and villages in and around Homs city, which has seen intense fighting since last month between the two sides.
Analysts believe that the outcome of the struggle for this strategic city will have a great impact on the course of the conflict, in which now the Syrian government apparently has the upper hand.
The UN now put the death toll in the 28-month-long conflict at about 93,000, but activist groups such as the Syrian Observatory of Human Rights reported much higher numbers. English News CN: Shells hit Damascus as Syrian troops gain more ground in Homs
WEB Notes: Isaiah 17:1