Russia expressed fear on Tuesday that the conflict in Syria between President Bashar Assad and rebel forces that began nearly two years ago could be protracted with no clear outcome.

"You know at first the forecasts were two to three months, four, and it is already two years," Deputy Foreign Minister Mikhail Bodganov was quoted as saying by Russian news agencies.

A group of around 150 people gathered in front of the German embassy in Ankara on Tuesday, protesting against the deployment of Patriot missiles near the Syrian border.

Demonstrators chanted slogans, including "Germany, take your Patriots and get out of Turkey!"

Syrian warplanes and tanks pounded rebel strongholds in Damascus province on Tuesday, a watchdog said, as a pro-regime daily reported clashes in a camp housing Palestinian refugees.

Fighter jets launched strikes on the town of Douma, northeast of Damascus, and overflew parts of Eastern Ghuta region, home to some of the rebel Free Syrian Army's fiercest and best-organized groups, said the Syrian Observatory for Human Rights.

Four buses carrying Russian citizens escaping the Syrian civil war crossed the Masnaa border post on Tuesday to travel to Moscow via Beirut airport.

A Russian embassy official traveling with the group said about 80 people, mostly women and children, are on the buses.

Prime Minister Najib Miqati discussed with Saudi Crown Prince Salman bin Abdulaziz ways to steer Lebanon clear of the developments in the region, the PM's press office said in a statement on Tuesday.

It said the meeting was held on Monday night in the presence of Saudi Foreign Minister Prince Saud al-Faisal and the Lebanese delegation to Riyadh that included FM Adnan Mansour, Finance Minister Mohammed al-Safadi, Economy Minister Nicolas Nahas and Industry Minister Vrej Sabounjian.

U.N. leader Ban Ki-moon and his Syria conflict envoy hit out Monday at "outside powers" for providing arms to rebels and the government that are fueling the murderous death toll.

The U.N. secretary-general and U.N.-Arab League envoy Lakhdar Brahimi both expressed "anguish" at the carnage in the 22-month-old conflict and the major powers' failure to agree to a stance on the war to push the two sides into talks, said Ban's spokesman Martin Nesirky.

Interior Minister Marwan Charbel shied away from confirming a report that Syrian rebels would set free nine Lebanese pilgrims held since May in return for the release of 1,000 Syrian opposition detainees.

In remarks to Voice of Lebanon radio (93.3), Charbel said General Security chief Maj. Gen. Abbas Ibrahim took with him to Qatar a file detailing the negotiations carried out by the Lebanese authorities since 11 men were kidnapped on May 22 on their way back from a pilgrimage to Iran.

More than 30 people, both civilians and pro-regime militiamen, were killed Monday in a suicide car bombing in the town of Salmiyeh in the central province of Hama, the Syrian Observatory for Human Rights said, reporting another blast in an upscale Damascus district.

A high-ranking regime official confirmed to Agence France Presse that dozens were killed in the Hama attack, which the Britain-based Observatory said targeted a building used by loyalist paramilitary fighters.

The U.N. said Monday it will conduct a major humanitarian operation in Syria, where nearly two years of conflict have left staggering daily death tolls and ravaged the economy and infrastructure.

"It has to be a big U.N. humanitarian operation in Syria. That is what the people expect of this mission," said John Ging, the director of operations for the Office for the Coordination of Humanitarian Affairs (OCHA).

Arab League chief Nabil al-Arabi said Monday that Syria peace envoy Lakhdar Brahimi's mission had not brought a "glimmer of hope" in ending the bloodshed, and urged U.N. action to enforce a ceasefire.

"All contacts (with the warring sides and international actors) made by Brahimi have thus far not yielded a glimmer of hope to end this crisis," Arabi told leaders meeting for an Arab League economic summit in Riyadh.