(ANSA-AFP) - HELSINKI, MAY 12 - Finland's president and prime minister said on Thursday they were in favour of joining NATO and a formal decision would be taken this weekend, after Russia's war in Ukraine sparked a swift u-turn in opinion. "Finland must apply for NATO membership without delay," President Sauli Niinisto and Prime Minister Sanna Marin said in a joint statement. Niinisto has often served as a mediator between Russia and the West. "NATO membership would strengthen Finland's security. As a member of NATO, Finland would strengthen the entire defence alliance," the statement said. A special committee will announce Finland's formal decision on a membership bid on Sunday, the statement added. The two leaders had been widely expected to come out in favour of joining the Western military alliance. "Joining NATO would not be against anyone," Niinisto told reporters on Wednesday, amid Russian warnings of consequences if Helsinki were to seek membership. His response to Russia would be: "You caused this. Look in the mirror," he said. As recently as January, amid tensions between the West and Russia, Marin said a bid would be "very unlikely" during her current mandate, which ends in April 2023. (ANSA-AFP).