The Japanese government believes North Korea may go ahead with a nuclear test or other provocation, Cabinet Secretary General Hirokazu Matsuno said at a news conference.

"We know that North Korea has expressed outrage over U.S. and South Korean military exercises. The Japanese government believes that North Korea may also engage in other provocations, including nuclear weapons tests.

"I would like to refrain from commenting on North Korea's future actions, the government is determined to protect the lives and peaceful existence of its citizens and will collect and analyze information while remaining vigilant,'' Matsuno said.

North Korea conducted missile launches twice a day on Wednesday and Thursday. On Thursday morning, three missiles were fired, one of which was believed to be an intercontinental missile. An air alert was issued in Japan due to the risk that the missile would fly over the country's territory. However, this did not happen, and the missile probably crashed before reaching Japanese territory.