Tartus has itself largely escaped the conflict in Syria, but posters of its sons killed fighting for the regime elsewhere in the country line the western city's main road.

A wall in the central bus station is a tapestry of pictures of the dead, most of them young, posing in fatigues with Kalashnikovs.

Iran is considering sending observers to monitor the June 3 presidential election in its key regional ally Syria, the foreign ministry said on Tuesday.

Shiite Iran is a staunch supporter of President Bashar Assad's regime, who has been battling mostly Sunni rebels who have been trying to oust him since the conflict erupted in March 2011.

Rocket fire by Syrian military helicopters killed at least 10 people in the northern town of Azaz on Tuesday, a monitoring group said.

The air raid came hot on the heels of hours of a rocket strike on the nearby town of Marea which killed 13 people, 10 of them children, on Monday night, the Syrian Observatory for Human Rights said.

Lebanon is under massive pressure as tens of thousands of refugees fleeing the war in neighboring Syria continue to stream in, likely reaching a total of 1.5 million people by the end of the year and heightening tensions in the tiny, overburdened country, U.N. officials said Monday.

The number represents one third of Lebanon's estimated population of 4.5 million, and unlike Turkey and Jordan, Lebanon has no refugee camps for Syrians, who are scattered all over in informal settlements, living with relatives or renting homes.

The historic Christian town of Maalula stands a shadow of its former self, abandoned and war-scarred, a month after Syrian government forces expelled Islamist rebels.

In the main square, with its posters of President Bashar Assad and slogans daubed on walls singing his praises, a handful of soldiers lounge in the spring sunshine.

More than 162,000 people have been killed in Syria since the conflict broke out in March 2011, the Syrian Observatory for Human Rights said in a new toll published Monday.

The Britain-based monitoring group, which relies on a network of sources on the ground, said it had documented the deaths of 162,402 people.

One hundred and twenty Palestinian children in Yarmuk were Sunday allowed out of the besieged refugee camp in southern Damascus to sit public exams, the U.N. agency for Palestinian refugees said.

"UNRWA arranged for the (120) students temporarily to leave Yarmuk to enable them to participate in nationwide state exams for ninth graders," said the agency's spokesman Chris Gunness.

Syrian authorities on Sunday urged a mass turnout in a June 3 presidential election branded a "farce" by the opposition.

"Whoever abstains from exercising his constitutional duty would be turning his back on his national obligation at a time when his nation is calling on him," parliament speaker Mohammed al-Lahham said.

The chief of Syria's air defense forces, General Hussein Isaac, has been killed in combat near Damascus, a security official told Agence France Presse on Sunday.

The general died of wounds suffered in fighting at Mleiha, a key battleground southeast of the capital, making him one of the few top-ranking officers whose deaths have been announced during Syria's three-year war.

A Syrian court has brought some 30,000 lawsuits over acts related to "terrorism" in the past two years, a pro-regime newspaper in the war-torn country said Sunday.

Among those accused were around 300 citizens of Arab countries other than Syria, said Al-Watan newspaper, which is close to the regime of President Bashar Assad.