Finland's president on Wednesday signed a 10-year security deal with Ukraine in Kyiv where President Volodymyr Zelenskiy said he believed Russia planned to mobilise 300,000 new troops for its war by June. But Kremlin spokesman Dmitry Peskov, quoted by Russian news agencies, said the Ukrainian president's assertion about a new Russian mobilisation was untrue.

The pact signed by President Alexander Stubb and Zelenskiy made Finland the eighth NATO member this year to commit to long-term security cooperation and defence backing for Kyiv as it battles to hold back Russian forces.

Finland, which shares a 1,340-km (830-mile) border with Russia, joined NATO a year ago.

Stubb said Finland would also send 188 million euros ($203 million) in additional military aid, including air defences and heavy-calibre ammunition. That sum took Finland's overall defence contribution to around 2 billion euros during the war.

"We are not giving this military support only for Ukraine to defend itself, we are giving this military support for Ukraine to win this war," Stubb told a joint news conference in Kyiv.