North Korea on Tuesday reportedly conducted a huge live-fire drill that involved up to 400 artillery pieces, which may have been supervised by the country’s leader, Kim Jong Un.
South Korea’s Yonhap news agency, citing an unnamed government source, reported that Pyongyang appeared to have deployed a number of long-range artillery units in the region of Wonsan, which is a coastal North Korean area.
South Korea’s military did not confirm the report, but told the news outlet that it is “firmly maintaining readiness.”
There was speculation that the North might carry out another nuclear or missile test.
News of the live-fire drill comes after the USS Michigan, a nuclear powered Ohio class submarine, pulled into the South Korean port of Busan for a hull check.
The Ohio class submarine will later join the USS Vinson aircraft carrier strike group for exercises in the Sea of Japan.
According to senior U.S. defense officials, the USS Vinson aircraft carrier strike group is in the Philippine Sea in waters south of Japan.
When asked about the USS Michigan, Lieutenant commander Matt Knight with U.S. Pacific Fleet told Fox News in a statement the submarine was on “routine deployment.”