FILE PHOTO: Russia's Foreign Minister Sergei Lavrov attends the 77th Session of the United Nations General Assembly at U.N.

UNITED NATIONS, Sept 24 (Reuters) - Russia's top diplomat on Saturday said regions of Ukraine where widely-derided referendums are being held would be under Russia's "full protection" if they are annexed by Moscow, amid fears Russia could further escalate the conflict and even use nuclear weapons.

"Following those referendums, Russia of course will respect the expression of the will of those people who for many long years have been suffering from the abuses of the neo-Nazi regime," Lavrov said at a news conference after he addressed the assembly.

Asked if Russia would have grounds for using nuclear weapons to defend annexed regions of Ukraine, Lavrov said Russian territory, including territory "further enshrined" in Russia's constitution in the future, "is under the full protection of the state.".

"All of the laws, doctrines, concepts and strategies of the Russian Federation apply to all of its territory," he said, also referring specifically to Russia's doctrine on the use of nuclear weapons.

The comments came after an explicit warning on Thursday by former President Dmitry Medvedev, an ally of Russian President Vladimir Putin, that any weapons in Moscow's arsenal, including strategic nuclear weapons, could be used to defend territories incorporated into Russia.

The likely annexation of Ukrainian territory raises the question of how Russia might respond to the use of Western weapons in those regions.

Asked whether he could foresee future talks with the United States to make Russia feel more secure about what it calls NATO encroachment, Lavrov said it was the West that had broken off previous discussions.

When asked if Russia was coming under any pressure from China to end the war, Lavrov said: "You may tell your readers, listeners, viewers that I avoided to answer your question.".