North Korea fired two unidentified projectiles off its east coast on Saturday, South Korea’s military said, a day after the North threatened to remain America’s biggest threat in protest of U.S.-led sanctions on the country.

South Korea’s Joint Chiefs of Staff said in a statement that the launches were made from the North’s northeastern Hamgyong province on Saturday morning.

The statement said South Korea’s military is monitoring possible additional launches by North Korea. But it gave no further details such as what type of projectiles were launched.

The Japanese government said North Korea appears to have fired missiles, but they caused no damage and did not land in Japanese waters.

The launches came after the United States and South Korea ended their regular military drills this week. North Korea called the drills an invasion rehearsal and conducted a series of missile and other weapons tests.

North Korea’s foreign minister said Friday his country will try to remain “America’s biggest threat” if the United States continues to confront the North with sanctions.

Foreign Minister Ri Yong Ho also called U.S. Secretary of State Mike Pompeo a “poisonous plant of American diplomacy” and vowed to “shutter the absurd dream” that sanctions will force a change in Pyongyang.

Ri’s blistering rhetoric and the projectile launches may dim prospects for an early resumption of nuclear negotiations between the countries. The top U.S. envoy on North Korea, Stephen Biegun, said Wednesday that Washington was ready to restart the talks, a day after the U.S.-South Korean military drills ended.