Russian Foreign Minister Sergei Lavrov says Western countries are not living up to their obligations on Syria.
Lavrov also said the United States wanted to put forward additional conditions before implementing a deal on Syria to end the conflict.
The foreign minister further said Russia would demand a very thorough investigation into a strike on an aid convoy in Aleppo last week.
The United Nations said at least 18 trucks in a 31-vehicle convoy were destroyed last Monday. The airstrike killed around 20 people, including one staff members of the International Federation of Red Cross and Red Crescent Societies.
US officials have oscillated between blaming the Syrian government and the Russian military for an aid convoy attack which both sides deny.
Russia has called for an independent investigation into the attack, saying an armed US drone was in the vicinity of the humanitarian aid convoy that was hit by the airstrike.
Lavrov earlier said that the humanitarian situation in Syria would not be improved without eradicating the terrorist groups fighting against the government of President Bashar al-Assad.
He criticized Washington for not doing enough to rein in militants in Syria to protect the truce deal, saying continued violations of the ceasefire by militants made it “senseless” for Damascus to stick to the agreement.