Iraqi Prime Minister Nuri al-Maliki heads to Moscow on Monday to boost defense and trade ties, but events in Syria loom large over talks between two states criticized over their support for Damascus.

Maliki's visit, his first to Russia in three and a half years, comes with Baghdad and Moscow accused of helping prop up embattled President Bashar Assad during a 19-month uprising which has left more than 31,000 dead.

Mitt Romney will call for a U.S. change of course in the Middle East on Monday, saying President Barack Obama's muddled strategy has failed to confront the challenges of extremism.

The Republican White House hopeful, offering a foreign policy vision that he and his campaign believe differs sharply from Obama's, said he would keep Iran in check, chase terrorists in Libya, put conditions on U.S. aid to Egypt and help arm Syrian rebels.

One person was killed in a car bomb attack on a street in central Damascus on Sunday where the police headquarters is located, Syrian state media said, as the Turkish army returned fire after a shell launched from Syria struck the southeastern Turkish border village of Akcakale, where five civilians were killed last week.

"A martyr fell in the terrorist attack," said the official news agency SANA, shortly after state television reported the car bombing on Khaled bin al-Walid Avenue.

Former minister Michel Samaha's personal computer represents a “valuable treasure” for the security agencies because it will reveal further details about his plot, a media report said on Sunday, as Mustaqbal bloc MP Ziad al-Qaderi warned of attempts to wrap up the case by claiming that the seized explosives were targeted at resisting Israel.

Lebanese security agencies unveiled the involvement of Syrian President Bashar Assad's adviser Buthaina Shaaban in the case “given the fact that Samaha, who owned three cellphones, used to regularly record all his phone conversations throughout the period of three years, before copying them to the computer that was seized on the day his house was raided by Intelligence Bureau agents,” security sources told al-Mustaqbal newspaper in remarks published Sunday.

Rebels cemented their control of Syria's northern frontier with Turkey after fierce clashes with the army, as their bastions in other parts of the country came under heavy shelling on Sunday.

As the fighting raged, Syrian state television said that government forces had pushed rebels out of two of their strongholds in Damascus province, Qudsaya and Hameh, where a watchdog said the bodies of 10 men were found.

Discouraged by lack of U.S. support, Saudi Arabia and Qatar have stopped short of arming Syrian rebels with the heavier weapons that could turn the tide of the war, The New York Times said Saturday.

Without the heavy weaponry, the rebels are only able to maintain a stalemate with President Bashar Assad's better-armed security forces, possibly prolonging the brutal war that began nearly 19 months ago and has already killed more than 31,000 people.

Hizbullah is “covertly providing men and support to the Assad government and currently has about 1,500 members inside Syria,” British newspaper The Times has quoted a Syrian defector as saying.

The claims come amid reports of Hizbullah fighters, including a senior founder member of the organization, being killed in Syria and buried in Lebanon.

A series of leaked Syrian documents have revealed that Hizbullah was involved in the December 12, 2005 assassination of prominent journalist and MP Gebran Tueni, chairman of the board of directors of An Nahar newspaper, Al-Arabiya television reported on Saturday.

“With the help of members of the intelligence department of Lebanon's Hizbullah, Mission 213, which was assigned to them on December 10, has been successfully accomplished with excellent results,” a document dated December 12, 2005 says.

Syrian Vice President Farouq al-Sharaa "is a man of reason" who could replace President Bashar Assad as the head of a transition administration to stop Syria's civil war, according to Turkish Foreign Minister Ahmet Davutoglu.

"Farouq al-Sharaa is a man of reason and conscience and he has not taken part in the massacres in Syria. Nobody knows the (Syrian) system better than him," Davutoglu said Saturday on the public television channel TRT.

Forty government soldiers and nine rebels were killed on Saturday when rebels took a town in the northwestern province of Idlib near the border with Turkey, the Syrian Observatory for Human Rights said.

"The clashes at Khirbat al-Joz... ended when fighters of the rebel brigades took control of the area," said the Britain-based watchdog.