North Korea fired three short-range ballistic missiles, following weeks of heightened tensions between Washington and Pyongyang.

The missile launches come as tens of thousands of South Korean and US troops take part in joint military drills in the south, which Pyongyang views as a highly provocative rehearsal for an invasion of its own territory.

A spokesman for US pacific command said two of the missiles failed in flight and the third blew up “Almost Immediately”.

He said none of the missiles, which were launched near Kittaeryong, had posed a threat to either North America or the US Pacific Territory of Guam.

The spokesman said the first and third missiles failed in flight. The second missile launch appears to have blown up almost immediately, adding that the launches happened over a span of 30 minutes.

The launches came as North Korea State media reported that leader Kim Jong-UN oversaw a military exercise simulating a special forces assault on South Korean border islands involving aircraft, “Multiple-missile launchers” and howitzers.

Shells hit islands standing in for South Korea’s Paekryong and Taeyonphyong islands while special forces landed in rubber boats or parachuted in and “wiped out the desperate enemy with various combat methods.

Kim Jong-UN expressed great satisfaction over the successful target-striking contest.