PRAGUE — The heads of nine European NATO members on Sunday issued a joint statement backing a path to membership for Ukraine in the U.S.-led security alliance, and calling on all 30 NATO nations to ramp up military aid for Kyiv.

Ukrainian President Volodymyr Zelensky made a surprise move Friday to apply for fast-track NATO membership, in response to Russia’s annexation of four regions of Ukraine.

NATO membership needs approval from all 30 members and Ukraine is unlikely to join anytime soon. Being a country already at war complicates the request.

The nine NATO countries in Central and Eastern Europe fearful that Russia could target them next if it isn’t stopped in Ukraine urged a response to the annexation.

The leaders of Czechia, Estonia, Latvia, Lithuania, North Macedonia, Montenegro, Poland, Romania and Slovakia published a statement on their websites Sunday saying: “We support Ukraine in its defense against Russia’s invasion, demand (that Russia) immediately withdraw from all the occupied territories and encourage all allies to substantially increase their military aid to Ukraine.”

It said the leaders “firmly stood behind the 2008 Bucharest NATO Summit decision concerning Ukraine’s future membership.” At the 2008 summit, NATO members welcomed Ukraine and Georgia’s aspirations to join, but declined to provide a clear timeline for the two countries’ possible ascension. Sunday’s letter didn’t mention a timeline, either.

Asked Friday about Zelensky’s application for accelerated NATO membership, White House national security adviser Jake Sullivan said the application process in Brussels “should be taken up at a different time.”

NATO Secretary-General Jens Stoltenberg was noncommittal when asked about Zelensky’s appeal to join.

Dmitry Medvedev, deputy head of Russia’s Security Council chaired by Putin, derided the move, saying that Zelensky’s request amounts to “begging NATO to accelerate the start of World War III.”

Spurred into action by security concerns over Russia’s invasion, Finland and Sweden officially applied to join NATO in May using an accelerated procedure. Most member countries have already ratified their applications and the two Nordic nations are on track to join in record time.