The violence was reported as political forces that claim leadership of the country's rebel movement squabbled about how a new Syria might look.
Two car bombings were reported, with differing accounts of casualties and damage.
The government's official news agency, SANA, said two people were killed and 10 injured in a blast at a security checkpoint. Human rights groups said as many as 50 government soldiers were killed and scores more injured, The New York Times reported.
A second car bomb went off in the heavily guarded Damascus neighborhood Mazzeh 86 -- home to many of the minority Alawite Muslims loyal to President Bashar Assad -- killing five people and injuring 30, the Syrian Observatory said.
Heavy shelling killed five people in southern Damascus, SANA said, but unverified Internet videos suggested the toll was much higher.
Syrian opposition factions were at odds in talks seeking to forge unity Washington says is needed to boost U.S. support and oust the Assad regime.
The Syrian National Council, the main exiled opposition coalition, based in Istanbul, Turkey, disagreed with a U.S.-backed proposal to set up a larger umbrella group the SNC would be part of but not dominate, the BBC reported.
The new group, proposed by well-known exiled dissident Riad Seif, would include representation of rebel fighters, opposition military councils and minority groups such as Kurds, Syria's largest ethnic minority, as well as minority Christians and Alawites.
Assad and many of his top security chiefs are adherents of the Alawite sect, an offshoot of Shiite Islam.
U.S. Secretary of State Hillary Clinton called last week for an overhaul of Syria's exile-led opposition political coalition, saying the SNC had outlived its usefulness and should be replaced by the new group. She said many leading SNC figures hadn't been in Syria for decades.
Seif told reporters on the first day of a four-day meeting in Doha, Qatar, Sunday the new group, called the Syrian National Initiative, would not replace the SNC.
"The initiative is not a substitute for the Syrian National Council, but the SNC should be an important part of it," he said. "To bring down the regime, we need 1,000 national councils."
The SNI would have about 50 members, including at least 15 from the SNC and is envisioned as becoming a unified government in exile, possibly by next month, the BBC said.
The exile government of technocrats would then hold a conference in Morocco to gain international recognition, Seif said.
"Maybe 100 countries [at the Morocco conference] will recognize this new leadership as the legitimate and only representative of the Syrians," Seif said.
Seif said Sunday he had no intention of leading the government in exile, pointing out he was 66 and had health problems. Seif has cancer.
"I will stick to helping form a political leadership which will satisfy the Syrian people and the world," he said.
The first day of talks took place as at least 234 people killed in Syria, the opposition Local Coordination Committees of Syria said. The dead included 100 reported killed in Damascus and its suburbs, including nine people "field executed" in the suburban town of Sabinah, a former Palestinian refugee camp, and 22 killed in regime shelling of Yarmouk Camp, another former Palestinian refugee camp in Damascus now at the heart of a struggle for the capital's southern suburbs.
Syrian rebels said last week they'd begun arming anti-regime Palestinians living in Yarmouk Camp to fight pro-regime Palestinians in the same enclave.