Russia wields a veto at the UN Security Council and the remarks are a blow to hopes of a fresh initiative there.
International outrage has been expressed at the massacre of 108 people - mostly women and children - in Houla.
Neighbouring Turkey is expelling all Syrian diplomatic staff in Ankara.
The move goes further than the co-ordinated action by a number of other countries, which restricted their expulsions to the most senior staff, although Syrian consular staff in Istanbul will remain.
Turkey's foreign ministry said it was "out of the question to remain silent".
In apparent retaliation for the diplomatic expulsions, Syria gave the Dutch charge d'affaires - one of the few remaining top-level Western diplomatic representatives in Damascus - 72 hours to leave.
Watch from CNN: