Blinken will travel on June 1-2 to Helsinki after a meeting of the Western alliance's foreign ministers in Oslo. He will first visit Sweden, which is also seeking to join NATO, and will meet all three countries' prime ministers.

In Helsinki, Blinken will meet deliver a speech "to highlight all the ways in which Russia's aggression against Ukraine has been a strategic failure," State Department spokesman Matthew Miller said.

Blinken will outline "our continued efforts to support Ukraine's defense of its territory, sovereignty and democracy in pursuit of a just and durable peace," he said.

Finland and Sweden, which long kept an official veneer of neutrality to avoid conflict with Moscow, both sought membership in NATO after Russia's February 2022 invasion of Ukraine, which had unsuccessfully sought to join the alliance.

Finland officially joined NATO, whose members commit to common defense, in April. Turkey and Hungary have yet to give their blessing for Sweden to join NATO, whose accession decisions need unanimity.

Turkish President Recep Tayyip Erdogan has pressed Stockholm over the presence in Sweden of members of the Kurdistan Workers' Party (PKK), which Ankara considers terrorists.

Western diplomats have voiced guarded hope that Turkey will lift its objections after Sunday's second-round presidential election.

Blinken's visit in Sweden will be to the northern city of Lulea where he will take part in talks of the US-EU Trade and Technology Council, which among other issues has looked to set common standards in the face of China's advances.