Foreign and defence ministers from the 30-nation North Atlantic Treaty Organization held video talks to try to fine tune proposals to reform the military alliance before the showcase meeting including US President Joe Biden in Brussels on June 14.

"We have just experienced an outrageous incident with the massive intervention by Belarus in civilian air traffic," Annegret Kramp-Karrenbauer said ahead of the talks.

"This makes it clear how great the challenges are that we are facing -- be it from Russia, be it from China, be it from new technologies."

She insisted it was "very important that we strengthen our ability to act together, for example ... with common means".

Belarus leader Alexander Lukashenko caused outrage last month by scrambling a fighter jet to divert a Ryanair flight and arresting a dissident journalist onboard.

NATO condemned the "unacceptable act" and said it was limiting access by Belarusian diplomats to its headquarters.

The fresh tensions on its eastern flank come as members states are eyeing a push to modernise the seven-decade alliance founded in the wake of the World War II to counter the Soviet Union.

Allies have moved to bolster their capabilities in the face of a more aggressive Russia and are also increasingly turning their attention to the rising might of China.

NATO Secretary General Jens Stoltenberg is pressing for a raft of changes including bolstering common funding for defence and deterrence and increasing political coordination between allies.

Some members remain opposed to the proposal for more joint spending arguing that it could take away funds from national defence budgets.

"All this money is money that won't go toward increasing national budgets and a European defence effort that benefits NATO," French defence minister Florence Parly told Politico.

Stoltenberg insisted there was "no contradiction" between national and NATO efforts and said he was confident leaders would agree an "ambitious" agenda.

"Spending together is a force multiplier, it's an efficient way of spending, and it also sends a very clear message to our own populations, and on to any potential adversaries," he told a press conference.

Former US president Donald Trump strained ties with NATO allies as he lambasted them for not spending enough on their own defence.

Biden has moved quickly to reassure allies that he will rebuild ties -- but his decision to withdraw troops from Afghanistan has left NATO scrambling to come up with a new plan.

Allies are rushing to hatch together a plan to secure their embassies as NATO's military mission pulls out after almost two-decades of involvement.

Stoltenberg said the alliance was working on ways to help keep key infrastructure working like Kabul airport and train Afghan special forces outside the country.

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