Syrian rebels downed an army helicopter for the first time on Tuesday with a ground-to-air missile from newly acquired stocks, a watchdog said, in a potential turning point for the 20-month conflict.

A car bomb hit a regime security post near Damascus and clashes raged around the capital, as rebels further tightened the noose around the key northern city of Aleppo.

Russia only has a "working relationship" with Syrian leader Bashar Assad, Russian Prime Minister Dmitry Medvedev said on Tuesday, insisting that special ties were a thing of the past.

"There are no special or privileged relations with President Assad," Medvedev said during an official visit to France.

Consumer prices in Syria have jumped by up to two-thirds this year, driven by deteriorating security, increased transport costs and unfavorable exchange rates, a pro-regime daily reported Tuesday, citing a government economist.

"The (price) increase of foodstuffs and merchandise depends on the exchange rates and the cost of transportation and labor," Ziad Hazaa, director of economy and internal trade at the ministry of economy told al-Watan newspaper.

U.N. Secretary General Ban Ki-moon is due to visit Syrian refugee camps in Turkey next week and to meet top officials including Prime Minister Recep Tayyip Erdogan, an official said Tuesday.

More than 120,000 Syrians have crossed into Turkey to flee the deadly violence that has engulfed their home country for 20 months, according to official figures, although the actual number is likely to be much higher.

Fighting raged around the Syrian capital Damascus and in northern Syria, where at least five people died in an air strike near an olive press, a watchdog said.

Fighting has raged around Damascus since summer, when the army launched an intensive operation to drive rebels out of their strongholds near the capital, particularly in southern districts.

Japan said Tuesday it was expanding the reach of its sanctions against the Syrian government, in a gesture ahead of a meeting this week in Tokyo aimed at increasing pressure on the regime.

In September last year Tokyo imposed a freeze on assets held in Japan by the Syrian president Bashar Assad and military leaders, in concert with European countries and the United States.

Human Rights Watch on Tuesday called on Syria's army to stop using cluster bombs, two days after at least 11 children were killed in an air strike on the town of Deir Assafir south of Damascus.

"This attack shows how cluster munitions kill without discriminating between civilians and military personnel," said Mary Wareham, the New York-based rights group's arms division advocacy director.

A car bomb hit a police checkpoint in a town southwest of Damascus on Tuesday morning, as the army deployed in large numbers nearby in a bid to suppress insurgents there, a monitoring group said.

"A car bomb exploded at dawn, targeting a military police checkpoint in Jdeidet Artouz," said the Syrian Observatory for Human Rights. "This was followed by intense shooting, as regular troops continued to be deployed in the fields between Kfar Sousa and Daraya."

U.N. Under-Secretary-General for Humanitarian Affairs Valerie Amos will visit Beirut on Tuesday to assess the situation of Syrian refugees and the humanitarian assistance being provided to them, the U.N. Information Center said.

Amos is scheduled to meet with Prime Minister Najib Miqati on Wednesday to find ways the U.N. and other agencies can best support the national efforts in addressing the needs of the Syrians who have been displaced as a result of the 20-month-old conflict that has killed more than 40,000 people.

General Security chief Abbas Ibrahim hinted that the case of the abducted Lebanese pilgrims in Syria will be resolved soon, without specifying any date, An Nahar newspaper reported on Tuesday.

According to the newspaper, Ibrahim met with the families of the kidnapped men on Saturday away from media spot light.