Antigovernment activists say the explosion a day earlier in Hama killed 70 people. The government blames a ´terrorist group´ and says 16 people died.

BEIRUT — United Nations monitors on Thursday visited the scene of an explosion in the Syrian city of Hama that antigovernment activists said had killed 70 people, many of them women and children.

Homes in the Mashaa al-Tayyar neighborhood were targeted Wednesday, they said, by rockets or shells fired by forces loyal to President Bashar Assad.

State media blamed the explosion on a "terrorist group" that accidentally set off an explosive in a house used to make bombs. Sixteen people died and 12 were injured, the report said.

After the explosion, the Syrian National Council, an opposition umbrella group, called for an emergency meeting of the United Nations Security Council to consider a resolution to protect civilians in Syria.

Since the U.N. monitoring mission began 10 days ago, at least 462 people have been killed, including 34 children, according to the Local Coordination Committees, a coalition of opposition groups. The "violent gunfire and bombing on Syrian cities haven´t stopped."

The Security Council has authorized a mission of 300 observers to monitor a cease-fire and implementation of a peace plan that was to end violence in the 13-month uprising against Assad. So far, only about a dozen monitors are in the country and it is expected to take weeks for the first 100 to arrive.

At least 20 people were reported killed Thursday, including 10 in Dair Alzour.

The mission has been criticized by government opponents, who say the presence of U.N. monitors brings only brief respites from violence. In some cases, towns visited by the monitors are attacked once they leave.

Neeraj Singh, a spokesman for the U.N. mission, told TV reporters that monitors visited the Damascus suburb of Duma on Wednesday. The next day, activists said, Duma was attacked, as it had been in the days before the visit.

Two monitors have been stationed in Hama, but activists said the U.N. presence didn´t protect them. Video said to be from Hama shot moments after the explosion or attack showed a massive white cloud and debris rising.

Other videos showed entire homes reduced to rubble and men digging through the debris with their hands searching for survivors and bodies. The lifeless body of a young girl, blood covering her face and pink shirt, was pulled from the rubble and carried through the crowd.

The Local Coordination Committees said at least 13 children and 16 women were killed. More than a dozen members of one family were killed, along with five members of a family that had fled the neighboring city of Homs, the group said.

Activists said many families had left Homs and were living in that neighborhood.

"We are killed in the ugliest ways," said one activist in Hama province, who did not want his name used.

Sandels is a special correspondent. (Copyright © 2012 Los Angeles Times 04/27/12)