NATO's recent move to strengthen its eastern border is aimed at deterring Russia, German Chancellor Olaf Scholz said on Sunday, adding that it should be clear to Moscow that the alliance will be ready to defend itself if necessary.

Speaking at the Eastern German Economic Forum also attended by Lithuanian Prime Minister Ingrida Simonyte, Scholz said Germany has played a leading role in NATO's presence in the Baltics on Russia's border, stretching back nearly a decade.

"And because the threat from Russia will continue, we and other allies decided last year to deploy additional units to the Baltic states and to station an entire brigade there permanently in future," Scholz said, according to a speech manuscript.

"But this turnaround in security policy is necessary to show Russia: We are prepared to defend every square inch of NATO territory against attacks."

He said diplomacy would only be successful from a position of strength, adding that it was absolutely vital that Baltic states could fully rely on NATO allies jumping to their defence in the event of a Russian attack.

"And that is a message for us. But it is also a message to Russia. Because the credibility of this promise is of course also part of Russia's calculation."

Russian President Vladimir Putin earlier this week warned NATO members against allowing Ukraine to fire their weapons into Russia, after several Western allies lifted restrictions imposed on the use of weapons donated to Kyiv.

NATO chief Jens Stoltenberg on Friday dismissed the warnings, saying the alliance had heard them many times before and self-defence was not escalation.