Finland, worried by Russian invasion of Ukraine, moves to join NATO; Kremlin warns of response

Finnish President Sauli Niinisto and British Prime Minister Boris Johnson (not pictured) hold a news conference, after signing a declaration between the UK and Finland to deepen their defence and security co-operation, amid Russia's invasion of Ukraine, at the Presidential Palace, in Helsinki, Finland, May 11, 2022. Frank Augstein/Pool via REUTERS

HELSINKI (Reuters) -Finland must apply to join the NATO military alliance "without delay", its president and prime minister said on Thursday, in a historic policy shift triggered by Russia's invasion of Ukraine.

Moscow said the move was a threat to it and warned it was ready to respond. But Finland's neighbour Sweden is also close to a decision on asking to join NATO after decades of following a neutral path.