The UN Security Council may impose tough sanctions against the Syrian government, the head of the Russian upper house's international affairs committee said.
"According to information leaked from a closed emergency meeting of the UN Security Council, the patience of Security Council's members has reached a limit," senator Mikhail Margelov said.
He added, however, that military intervention was unlikely.
A Russian Foreign Ministry official said on Tuesday that the use of sanctions against Syria would be counterproductive,
Syrian government forces launched more tank attacks on the city of Hama on Monday during an ongoing crackdown on protesters.
One report said four people had died. Security forces are reported to have killed dozens of people in the city on Sunday. Activists say about 130 people were killed.
The uprising against President Bashar al-Assad began in mid-March and has claimed hundreds of lives.