There is growing instability on the Syrian side of the armistice line on the Golan Heights, Israeli chief of staff Lieutenant General Benny Gantz told MPs on Tuesday.

"In the Golan Heights, there is an instability developing that is on the rise, as a result of events in Syria, including in the zone adjacent to the border," Gantz told the parliamentary committee on foreign affairs and defense.

Relatives of 11 Lebanese Shiite pilgrims abducted in Syria blocked Tuesday the airport road for around an hour, with some protesters describing the move as a “first warning” to Lebanese authorities.

Some of the protesters sat down in the middle of the street while no burning of tires was reported. Al-Jadeed television quoted protesters as saying that “the airport road will be totally blocked on Wednesday and Thursday as a first warning.”

Russia said on Tuesday it was prepared to see Syrian President Bashar Assad leave power in a negotiated solution to 15 months of bloodshed that has claimed more than 13,000 lives.

Deputy Foreign Minister Gennady Gatilov said a day after meeting mediator Kofi Annan in Geneva that Russia would back any peaceful settlement to the crisis as long as it did not involve the use of outside force.

Syrian authorities have agreed to give relief workers access to four key sites, the United Nations said on Tuesday following a meeting on scaling up humanitarian aid.

"We will have a presence in Homs, Idlib, Daraa and Deir Ezzor to start with," said John Ging, director of the coordination and response unit at the U.N. Office for the Coordination of Humanitarian Affairs (OCHA).

More than 2,000 Syrians fled to Turkey in the past three days, officials said Tuesday, pointing to an increase in refugee arrivals which had dipped following a peace plan in April.

The number of Syrian refugees in camps set up in southeastern Turkey reached 26,747 on Tuesday, up from 24,433 on Saturday, according to figures announced by Turkey's Disaster and Emergency Management Presidency (AFAD).

Syria's government declared on Tuesday that the ambassadors and staff of several Western countries as well as Turkey were personae non gratae.

"Some states recently informed heads of our diplomatic missions and embassy staff that they are unwelcome," the Foreign Ministry said in a statement, adding Syria was now designating the ambassadors of the United States, Britain, France and Turkey, among others, as personae non gratae.

A U.S. State Department team will visit Moscow this week to discuss the Syria crisis, a top official said Tuesday as Western pressure mounted on Russia to back new action against its Soviet-era ally.

"We are in the process of meeting (U.S. Secretary of State) Hillary Clinton's deputies who work on the Middle East and Syria in particular," Russia's Deputy Foreign Minister Mikhail Bogdanov told the RIA Novosti state news agency.

Russian President Vladimir Putin started a visit to China Tuesday aimed at bolstering a crucial alliance, with foreign policy to the fore as the neighbors seek to block action against Syria.

Putin will also meet the presidents of Iran and Afghanistan as part of a regional summit during the three-day visit, his first to Asia since starting an historic third term last month.

Two Jordanian Salafists have been arrested as they tried to cross the border into neighboring Syria to fight President Bashar Assad's forces, a security official and relatives said on Tuesday.

"Two men from the southern city of Maan were arrested Sunday on the border when they tried to illegally enter Syria," the security official told Agence France Presse.

Regime forces went on the offensive against rebels on Tuesday, seizing a town in the central province of Hama, as at least seven people including an army colonel were killed in violence across Syria, monitors said.

After three days of bombardment, troops and pro-regime militiamen backed by tanks and armored cars entered Kfar Zita, the Syrian Observatory for Human Rights said, adding that rebel fighters had withdrawn.