The Kremlin on Thursday praised Russian troops fighting in Ukraine as heroes who would go down in history and described the deaths of soldiers there as a tragedy.

Kremlin spokesman Dmitry Peskov also said President Vladimir Putin would convene Russia's Security Council later on Thursday but did not say what the group of top state officials and heads of defense and security agencies would discuss.

In a briefing with reporters, Peskov dismissed speculation that Russian authorities plans to introduce martial law following its invasion of Ukraine or that they will prevent men leaving Russia.

Russia calls its actions in Ukraine a "special operation" that it says is not designed to occupy territory but to destroy its southern neighbor's military capabilities and capture what it regards as dangerous nationalists.

Peskov said Russian casualties in the fighting in Ukraine – which the defense ministry put at 498 soldiers in a statement on Wednesday – were a source of grief.

"Of course, this is a great tragedy for all of us. At the same time, we all admire the heroism of our military," he said.

Peskov condemned the International Paralympic Committee for barring Russian athletes from the Winter Paralympics in Beijing, calling it a monstrous situation.

There had been threats of a boycott of the Games from other teams over Russia's invasion of Ukraine last week.

Peskov said Ukraine was "clearly not in a hurry" to hold to another round of diplomatic talks over the conflict and that he hoped the Ukrainian delegation would be able to attend discussions planned for Thursday.