BRUSSELS (AP) — NATO Secretary-General Jens Stoltenberg says Finland will become the 31st member of the military alliance on Tuesday.

“From tomorrow, Finland will be a full member of the alliance,” Stoltenberg told reporters in Brussels.

Stoltenberg said that Turkey, the last country to have ratified Finland’s membership, will hand its official texts to U.S. Secretary of State Antony Blinken on Tuesday as NATO foreign ministers gather in Brussels.

Stoltenberg said he would then invite Finland to do the same.

A flag raising ceremony to add the Finnish flag to those of the other members will take place at NATO headquarters at on Tuesday afternoon.