Russia said Wednesday it backed a call by the International Committee of the Red Cross to set up a daily two-hour truce in Syria but opposed establishing humanitarian corridors for reaching civilians.

The foreign ministry said Russia was growing "seriously concerned" about the humanitarian situation in Syria and was putting pressure on both President Bashar al-Assad and the armed opposition to halt the violence.

"We are seriously concerned by incoming reports about the difficult humanitarian situation in Syria," said Russian foreign ministry spokesman Alexander Lukashevich.

"We actively support the efforts of the International Committee of the Red Cross" to establish a truce, Lukashevich told a weekly press briefing.

"It is presumed that this pause will be used to provide humanitarian assistance to the nation's population."

But another top official said Russia was not backing a call by France to set up actual humanitarian corridors for delivering assistance to flashpoints such as Homs because these would require support from foreign troops.

"Creating these corridors would hardly be effective," Deputy Foreign Minister Gennady Gatilov said.

"This would require special mechanism and forces, and logically speaking, this could lead to the use of force, should things go wrong."

He said the idea backed by Moscow and the ICRC was to ensure "a humanitarian pause -- not humanitarian corridors,"

The Kremlin separately reported that President Dmitry Medvedev discussed the crisis by a telephone with Saudi King Abdullah.

"Dmitry Medvedev and King Abdullah exchanged views about the situation in the Middle East in the light of the events in Syria," the Kremlin said without providing further details.

Russia has firmly resisted foreign military intervention in the country and together with China vetoed two UN Security Council resolutions condemning Moscow's traditional ally Assad for the violence.

Gatilov said Russia was growing increasing concerned by reports that the armed opposition groups were receiving military assistance from abroad.

"That the armed opposition is receiving support is a well established fact," he told reporters.

"The shipments that cross the border from Lebanon.... support the armed opposition. We feel this only feeds and escalates the situation."

Russia has emerged as Assad's closest international ally and its support for a truce puts pressure on the regime to open the border to foreign supplies.

But Russia has refused to single out Assad for criticism and on Wednesday again called on both his forces and the armed opposition to end the violence.

"We once again urge all Syrian sides to end the violence. This concerns both the official authorities and the opposition, which must disassociate itself from extremists," foreign ministry spokesman Lukashevich said.