TOKYO — Japanese Prime Minister Shinzo Abe and US President Donald Trump agreed in telephone talks on Monday morning to keep urging North Korea, which continues to pursue nuclear weapon and ballistic missile development, to exercise self-restraint.

"I had an in-depth exchange of views with President Trump about the situation in North Korea," Abe told reporters after the leaders’ third such conversation this month.

"We completely agreed to strongly seek self-restraint from North Korea, which is still continuing its dangerous provocative acts," Abe said at the prime minister’s office. "The issue of North Korea’s nuclear and missile (development) is an extremely grave threat to security, not just for the international community but also for Japan."

North Korea is thought to be preparing to conduct further test-firings of missiles or a sixth nuclear test, possibly around the 85th anniversary of the founding of the Korean People’s Army on Tuesday.

Trump will also have a telephone conversation with Chinese President Xi Jinping, a White House official said in Washington on Sunday.

The Japanese Maritime Self-Defense Force and US Navy began on Sunday joint strategic maneuver and communication drills involving two Japanese destroyers and the US aircraft carrier Carl Vinson, which is headed for waters off the Korean Peninsula.

There had been confusion over the exact timing of the move northward to the Sea of Japan by the Carl Vinson Strike Group, which includes the aircraft carrier, two guided-missile destroyers and a cruiser, following a US Navy announcement on April 8 that conflicted with subsequent reports.

"We will keep dealing with (the issue) by continuing to coordinate closely with the United States and maintaining advanced surveillance and warning readiness," Abe said.

North Korea has said it is in the final stages of developing an intercontinental ballistic missile that could hit mainland US targets. Targets in Japan are within range of its shorter-range missiles, but their test-firing history has been checkered with failures. — KYODO