Polish Foreign Minister Radoslaw Sikorski said he discussed the possibility of increasing support for Ukraine with his counterparts from Germany, France, Italy, Spain, and Britain during a meeting in Warsaw on Tuesday.

Germany’s foreign minister vowed Tuesday her country would not be intimidated by Russia's new nuclear deterrent policy, saying Berlin made that mistake in the past but would not repeat it.

Annalena Baerbock told a news conference in Poland that Berlin will now heed the warnings of partners that border Ukraine. She was attending a meeting of foreign ministers of Poland, Germany, France and Italy.

"Putin is playing with our fear," Baerbock said. "He didn't just start doing this 1,000 days ago. He started back in 2014. And Germany in particular made the mistake back then, especially politically, of allowing itself to be intimidated by this fear and, above all, not listening to its partners, especially our Eastern European partners, who made it clear at the time: We must not rely on promises from the Kremlin. We must invest in our own security and protection."

Russian President Vladimir Putin on Tuesday signed a revised nuclear doctrine declaring a conventional attack on Russia by any nation that is supported by a nuclear power will be considered a joint attack on his country.

It follows President Joe Biden's decision to let Ukraine strike targets inside Russia with U.S.-supplied longer-range missiles.

The foreign ministers are discussing stepping up Europe's military support for Ukraine as well as ties with the United States under Donald Trump.

Trump says he expects Europe to make a greater effort for its own defense in the face of Russia’s war with Ukraine.

Sikorski, the meeting's host, said "we have agreed that Europe must take greater responsibility for its own security, and that includes a more balanced sharing of the burdens among NATO members."

Also present at the meeting is the European Union's upcoming chief of diplomacy, Kaja Kallas.

For "logistical reasons," the Ukrainian Foreign Minister Andrii Sybiha could not attend in person, Sikorski said.

Information from The Associated Press was used to compile this report.