BEIRUT - U.N. cease-fire monitors toured a rebel-held town in central Syria on Sunday with army defectors, while government troops stormed and shelled a Damascus suburb, activists said.

The shelling in Douma highlighted the need for more observers a day after the Security Council voted to expand the number of U.N. observers from 30 to 300 in hopes of salvaging an international truce plan marred by continued fighting between the military and rebels.

An eight-member team is already on the ground in Syria, and since Thursday has visited flashpoints of the 13-month-long conflict. Fighting generally halts when the observers are present in an area, but there has been a steady stream of reports of violence from towns and regions where they have not yet gone.

"This U.N. observers thing is a big joke," said Douma-based activist Mohammed Saeed. "Shelling stops and tanks are hidden when they visit somewhere, and when they leave, shelling resumes."

His comments reflect a widespread lack of faith among many Syrians in international envoy Kofi Annan's cease-fire plan for ending the violence in Syria and launching talks between President Bashar al-Assad and those trying to oust him. Syria's opposition and its Western supporters suspect Assad is largely paying lip service to the truce since full compliance - including withdrawing troops and heavy weapons from populated areas and allowing peaceful demonstrations - could quickly sweep him from power.

The state news agency SANA said U.N. monitors visited Hama on Sunday and met with the governor, while opposition activists said observers visited Rastan, a rebel-held town in central Syria.

Saeed, the activist, said two people were killed Sunday by indiscriminate firing in Douma, which was the scene of intense clashes between rebels and security forces before the U.N.-brokered cease-fire went into effect more than a week ago. The Syrian Observatory for Human Rights, a Britain-based opposition group with a network of activists on the ground, confirmed the deaths.