Syrian activists say government forces have shot and killed at least 20 people at a funeral procession in central Syria while U.N. military observers were in the area.

The activists say the shootings happened Tuesday in Khan Sheikhoun, near the city of Hama. The Britain-based Syrian Observatory for Human Rights said government forces committed a “massacre” in the presence of the U.N. observers who were in a four-vehicle convoy. There was no independent confirmation of the casualties.

Shortly after the shooting, a roadside bomb exploded near the U.N. convoy, damaging several of the vehicles. A video of the incident was posted on the Internet. The Norwegian general leading the U.N. mission in Syria, Robert Mood, told reporters in Damascus that he had spoken to all members of his team and confirmed they were safe.

Syrian dissidents also reported the killings of at least seven other people across the country on Tuesday. They said a blast killed four people in the coastal town of Banias, while fighting between government and rebel forces killed three people in the eastern town of Deir el-Zour.

Syrian state news agency SANA blamed the Banias explosion on armed terrorists who it says are leading the revolt.

White House spokesman Jay Carney said the United States is “deeply concerned” by Syria's escalating violence and “deepening sectarianism.”

Earlier Tuesday, General Mood said his mission has grown to more than 200 military monitors and has had a “calming effect” in parts of the country. Mood also said he is “impressed by the cooperation” of all parties with the U.N. team.

But, the relief group Doctors Without Borders said a team of foreign medics returning from a secret mission in Syria reported that people wounded in the uprising, and the doctors who treat them, are at risk of arrest or attack.

The group said the medics sneaked into the opposition hubs of Homs and Idlib after failing to get government permission to enter the country. Doctors Without Borders called on all sides in the conflict to fully respect health workers, medical facilities and the wounded.

In another development, the Syrian government said more than half of eligible voters turned out for a May 7 parliamentary election boycotted by opposition groups who said it had no credibility while security forces pursue a deadly crackdown on dissent.

Syrian election committee chairman Khalaf al-Izzaoui said Tuesday the voter turnout reached 51 percent, equivalent to 5 million people. There was no independent monitoring of the election, and opposition activists said there was little voting in towns and villages where security forces have been suppressing a 14-month-long opposition uprising.

The election was the first to be held since a February referendum approved a new constitution allowing the formation of new parties to compete with Syria's Baath-led coalition.

U.S. State Department spokeswoman Victoria Nuland said Tuesday it was “pretty ridiculous” for Syria to conduct the election in an environment of ongoing violence. She said the vote was “neither free, fair, transparent or representative of the Syrian people.”

Several new parties participated in last week's vote, which the government praised as a major political reform. But, the exiled Syrian National Council opposition group dismissed the new parties as government creations.

Syrian election chief al-Izzaoui read out a list of winning candidates on Tuesday for the 250-seat parliament, which has been dominated for decades by the Baath party of Syrian President Bashar al-Assad. The list included 30 women and one candidate who has described himself as an independent, Qadri Jamil. The Syrian official did not give a breakdown of votes by party or region.

The opposition SNC, meanwhile, said Tuesday that its members had voted to extend the term of their leader Burhan Ghalioun by another three months. Ghalioun, a secular academic, won more than half of the votes cast by members of the SNC's general secretariat at a meeting in Rome.

The United Nations says more than 9,000 people have been killed in violence related to the anti-government uprising which erupted more than a year ago. The Syrian government has blamed armed terrorist groups for much of the country's unrest.