Russia said it would not be "apologetic" about its military campaign and suggested Western powers were using the pressing need for aid deliveries in Syria for propaganda ends.
Russian Ambassador Vitaly Churkin was hitting back at France, Britain and their allies at the UN Security Council who were pressing Moscow over its anti-ISIL campaign in Syria.
The Security Council met at the request of New Zealand and Spain to discuss the humanitarian situation in Aleppo where the Syrian army, backed by Russian air power, was securing military achievements against Takfiri insurgents.
The meeting came on the eve of a crucial meeting in Munich of the 17-nation International Syria Support Group that is to chart a way forward for peace talks set to resume in Geneva on February 25.
Russian Foreign Minister Sergei Lavrov is to present ceasefire proposals at the Munich talks, but no details of the plan were released at the council meeting.
"Let me be clear about it: It's not a favor that we are asking to the Syrian regime and its allies, it's their obligation," French Ambassador Francois Delattre told reporters.
"The regime and its allies cannot pretend they are extending a hand to the opposition while, with their other hand, they are trying to destroy them," he said.
New Zealand and Spain proposed a humanitarian pause to shore up prospects for the peace talks after the opposition said it would not attend without an end to starvation sieges and air strikes.
"We do call on them to show decency and cooperate with the UN," said New Zealand Ambassador Gerard van Bohemen.
Russia's envoy said Moscow was ready to look at proposals for a humanitarian pause but that discussion would be needed to avoid the same outcome as in Yemen, where ceasefires never materialized.
"We are not about to be apologetic about what we are doing," Churkin told reporters after the meeting.
"We are there legally, at the invitation of the Syrian government."
"This propagandistic use of the Syrian humanitarian file is not going to deter Russia from doing the humanitarian work we are doing with the Syrian government," he added.
Churkin commented that the "changes in balance on the ground... should be taken as logical development in any armed conflict."