Updated

South Korea's Yonhap news agency says North Korea has test-fired three short-range projectiles into the Sea of Japan.

The South Korean Defense Ministry couldn't immediately confirm the report.

Such test firings aren't unusual. North Korea conducted a series of missile and artillery tests earlier this year.

They come during an unusually tense period between the Koreas. North Korea has threatened South Korea's leader, calling her a prostitute, and the South has vowed to hit North Korea hard if provoked. There has also been widespread speculation that North Korea is preparing for its fourth nuclear test.