Italian Admiral Giuseppe Cavo Dragone, chair of NATO's Military Committee, said that 32 defence chiefs from across the alliance would hold a video conference as a US-led diplomatic push seeks to end the fighting.
US General Alexus Grynkewich, NATO's supreme allied commander Europe, would take part in the talks, Dragone said on social platform X.
US President Donald Trump met last Friday with Russian President Vladimir Putin in Alaska and on Monday hosted Ukrainian President Volodymyr Zelenskiy and prominent European leaders at the White House.
Neither meeting delivered concrete progress.
Trump is trying to steer Putin and Zelenskiy towards a settlement more than three years after Russia invaded its neighbour, but there are major obstacles.
They include Ukraine's demands for Western-backed military assurances to ensure Russia will not mount another invasion in coming years.
"We need strong security guarantees to ensure a truly secure and lasting peace," Zelenskiy said in a Telegram post on Wednesday after Russian missile and drone strikes hit six regions of Ukraine overnight.
Kyiv's European allies are looking to set up a force that could backstop any peace agreement, and a coalition of 30 countries, including European nations, Japan and Australia, have signed up to support the initiative.
Military chiefs are figuring out how that security force might work.
The role that the US might play in is unclear. Trump on Tuesday ruled out sending US troops to help defend Ukraine against Russia.
Russia has repeatedly said that it would not accept NATO troops in Ukraine.
Attacks on civilian areas in Sumy and Odesa overnight into Wednesday injured 15 people, including a family with three small children, Ukrainian authorities said.
Russian strikes also targeted ports and fuel and energy infrastructure, officials said.
Zelenskiy said the strikes "only confirm the need for pressure on Moscow, the need to introduce new sanctions and tariffs until diplomacy works to its full potential".
Trump said on Monday he had begun arrangements for a face-to-face meeting between Putin and Zelenskiy, although the Kremlin has not publicly confirmed such a possibility and no venue was suggested.
French President Emmanuel Macron has said the summit could happen in Europe and proposed the Swiss city of Geneva.
Putin's ability to travel abroad is limited, however, because he is wanted by the International Criminal Court in The Hague on a warrant dating back to March 2023 for alleged involvement in the abduction of Ukrainian children.
More than 100 countries are ICC signatories and have a legal obligation to arrest the Russian leader on their soil.
Switzerland intends to ask the ICC to exempt it from sanctions in order to allow Putin in for a summit, according to a senior official in The Hague with direct knowledge of the request.
The official was not authorised to speak about the proceedings and spoke on condition of anonymity.
