SEOUL, South Korea — North Korea announced on Tuesday that Feb. 8, the day before the Winter Olympics open in South Korea, will be a national holiday honoring its army, raising the possibility that it will hold a large military parade in a show of force on the eve of the Games.

In recent weeks, South Korean officials have observed signs that the North, which is sending athletes to the Olympics, might be preparing for such a parade in its capital, Pyongyang, including large gatherings of troops and vehicles.

The North’s official Korean Central News Agency said on Tuesday that Feb. 8 would be commemorated as the country’s new Army Building Day. That holiday had previously been observed on April 25, the date when the North’s founding leader, Kim Il-sung, was said to have founded a guerrilla unit in 1932 to resist Japanese colonial rule.

Though the North has long said that its regular army was founded on Feb. 8, 1948, until now it had treated that date as less significant than April 25. This Feb. 8 will mark 70 years since the army’s founding, a milestone anniversary of the kind that North Korea often observes with enormous military parades, featuring columns of goose-stepping soldiers, tanks and missiles.