Polish Prime Minister Donald Tusk said on Thursday he was treating conciliatory comments from Russian President Vladimir Putin on the Ukraine crisis with caution.

"The NATO assessment, in line with ours, is that we should approach President Putin's statement with great caution," Tusk told a joint news conference with visiting NATO Secretary-General Anders Fogh Rasmussen.

"This is not yet the moment when we can announce with enthusiasm that the crisis is over. We both hope that perhaps Putin's words indicate some kind of a more optimistic scenario, but today it is too early for us to confirm that."

Rasmussen, commenting on assertions from Putin that Russian troops had pulled back from the border with Ukraine, said: "We noted the Russian statement, but up to now we have not seen any signs that the troops are actually withdrawing."

Asked about a Russian foreign ministry statement that Rasmussen must be blind if he could not see signs of the Russian troops pullback, Rasmussen told reporters: "I have very good vision."

Reuters