This video image taken from amateur video and broadcast by Bambuser/Homslive shows a series of devastating explosions rocking the central Syrian city of Homs, Syria, Monday, June 11, 2012. Live streaming video caught the devastation during one of the heaviest examples of violence since the uprisings began over a year ago. ( Photo/Bambuser/Homslive via AP video) MANDATORY CREDIT: BAMBUSER/HOMSLIVE

BEIRUT - Syrian forces barraged an eastern city with mortar shells as anti-government protesters were dispersing before dawn Tuesday, killing at least 10 people, while government troops kept up an offensive in a coastal province where Washington says regime forces may be preparing a massacre, activists said.

The violence comes as President Bashar Assad's regime faces mounting international pressure over brutal tactics against the opposition, with the U.N. accusing the government of using children as human shields. Monday's report also said children have been victims of detention, torture and sexual violence.

Amateur video of the mortar attack in Deir el-Zour showed dead people in a street as survivors screamed in panic and tried to remove their bodies. Other videos showed some of the wounded receiving treatment at a hospital. The Local Coordination Committees activist group and the Britain-based Syrian Observatory for Human Rights said 10 died in the barrage.

Bloodshed has spiked in recent weeks as both sides ignore an internationally brokered cease-fire that was supposed to go into effect April 12 but never took hold. The U.S. and its allies also have shown little appetite for getting involved in another Arab nation in turmoil.

The conflict began in March 2011 with mostly peaceful protests against the regime that were inspired by the Arab Spring wave of uprisings. But it has transformed into an insurgency as the opposition increasingly took up arms against a vicious government crackdown on dissent. Activists say more than 13,000 people have been killed.

Both activist groups also reported clashes in areas including the central province of Homs, the northern regions of Idlib and Aleppo and areas around the capital Damascus and the southern province of Daraa.

The Observatory said troops kept up an offensive in an eastern coastal region where the U.S. says President Bashar Assad's forces may be preparing a massacre. The group said regime forces shelled Haffah and neighbouring villages in Latakia province Tuesday for the eighth straight day, it said, as regime forces try to push through against stiff resistance. Activists say the government has brought in helicopter gunships to aid their offensive, an increasingly common practice.

The Haffah region is dominated by the Alawite sect and is close to Kardaha, which is the hometown of President Bashar Assad's family. Assad and most of Syria's ruling elite belong to the Alawite minority, an offshoot of Shiite Islam, while the Sunni Muslim majority makes up most of the opposition.

The United States had accused Assad's government Monday of using "new horrific tactics," while. State Department spokeswoman Victoria Nuland also said the regime "may be organizing another massacre" in Latakia, where U.N. monitors have been impeded.

Syria's Arab News Agency SANA reported Tuesday said that Syrian forces are still tracking down "terrorists," who it said had attacked the residents of Haffah.

It said that pursuit led to the killing of a number of gunmen, wounding others and arresting an unidentified number of them, adding that two Syrian troops were killed and some others wounded in the clashes.

Attempts to contact activists in Haffa did not succeed because of bad cellular connections.

State-run news agency SANA said a reporter and a cameraman for the pro-government Ikhbariya TV were wounded when their car was hit with bullets in Haffah on Monday.

The government restricts journalists from moving freely, making it nearly impossible to independently verify accounts from either side.

The U.N.'s special envoy on Syria has asked governments with influence to "twist arms" to halt the escalating violence in the country, his spokesman said Tuesday.

Ahmad Fawzi said the former U.N. Secretary-General Kofi Annan is also working to convene a diplomatic meeting soon to discuss the situation in Syria amid worsening fighting between government troops and opposition forces. Annan put forward earlier this year a six-point peace plan, including the cease-fire, to try end the violence.

"It is totally unacceptable and it must stop, and that is why Annan has invited governments with influence to raise the bar to another level, to the highest level possible, and twist arms if necessary, to get the parties to implement the plan," Fawzi told reporters in Geneva.

He didn't specify the countries that might be able to pressure the government of President Bashar Assad into halting its onslaught against the opposition, but Russia, China and Iran are considered Syria's closest and strongest allies.

The pro-government daily Al-Watan said Syrian troops were able to retake control of "large areas" of the rebel-held neighbourhoods of Khaldiyeh and Bab Sbaa in the central city of Homs, adding that the army planned to "expel all gunmen and terrorists" from the city.

Tarek Badrakhan, an activist in Khaldiyeh, denied the report, saying rebels have control of the whole neighbourhood and had repelled several attacks by the army. The Observatory also said that troops are heavily shelling the neighbourhood, but still trying to capture it.

Late Monday, the United Nations said children as young as 9 had been used as human shields and some as young as 14 had been tortured in detention. Children described being beaten, blindfolded, subjected to stress positions, whipped with heavy electrical cables, scarred by cigarette burns and in one case subjected to electrical shock to the genitals, the report said.

It quoted a witness as saying that, in a March 9 attack on the village of Ayn l'Arouz in Idlib province, several dozen boys and girls between the ages of 8 and 13 were forcibly taken from their homes and "used by soldiers and militia members as human shields, placing them in front of the windows of buses carrying military personnel into the raid on the village."

U.N. Secretary-General Ban Ki-moon on Monday demanded an immediate end to the "dangerous intensification" of violence across Syria and called on all countries with influence to urge the parties "to pull back from the brink."

News from © The Associated Press, 2012