Syrian government troops backed by tanks attacked three central towns Sunday in an attempt to stop round-the-clock protests there against President Bashar Assad's regime, killing at least five people and wounding scores of others, activists and a rights group said.

Activists said a school employee was killed and several students were hurt, four seriously, when a shell exploded near a school bus.

Security forces in several other parts of the country fired on crowds holding overnight demonstrations, causing casualties, activists said.

The new attack using military forces pointed to Assad's determination to crush the 2-month-old revolt, despite U.S. and European sanctions, including an EU assets freeze and a visa ban on Assad and nine members of his regime.

The uprising, which began in mid-March, is posing the most serious challenge to his family's 40-year rule. What began as a disparate movement demanding reforms has grown into a resilient uprising seeking Assad's ouster. Human rights groups say more than 1,000 people have been killed in the crackdown.

Sunday's military attacks targeted the towns of Rastan, Talbiseh and Teir Maaleh in the central province of Homs. Authorities had sealed off and isolated the towns by closing roads and cutting phone service, the activists said.

"The towns are under siege," one of the activists said.

The activists spoke on condition of anonymity, fearing government reprisals.

Residents of the towns have held anti-regime protests since the start of the uprising. Those protests have increased recently, with crowds taking to the streets day and night to call for the fall of Assad's regime, an activist said.

The Syrian Observatory for Human Rights said two people were killed in Rastan and four were wounded in Talbiseh. There were no immediate reports of casualties in Teir Maaleh.

An activist said at least three people were killed in Tabliseh. The activist said that nearly 100 wounded people were taken to hospitals in the central city of Homs.

The Local Coordination Committees in Syria, which help organize the protests, said security forces were detaining men in Talbiseh. They said people were blindfolded before being loaded to buses that took them to detention centers.

Also Sunday, human rights activist Mustafa Osso said security forces opened fire at about 8,000 protesters in the northeastern town of Deir el-Zour, wounding several people.

Click here to see the comments. Add yours now!