Jane Onyanga-Omara

USA TODAY

North Korea staged what is thought to be its largest live-fire drill Tuesday as it marked the 85th anniversary of the founding of its military, South Korean officials said.

Leader Kim Jong Un is believed to have attended the event, near the eastern port city of Wonsan, South Korean news agency Yonhap reported.

Experts predicted a possible nuclear test or ballistic missile launch to celebrate the anniversary, which did not occur.

In a further warning of its military might, North Korea said the United States will have to choose between political and military surrender if Washington launches a pre-emptive strike, Yonhap reported Tuesday.

"If the U.S. and warmongers run amok with a reckless pre-emptive strike, we will stage the most brutal punishment of a pre-emptive attack in the sky and land as well as at sea and from underwater without any warning or prior notice," said Rodong Sinmun, a spokesman for the ruling Workers' Party of Korea, according to Yonhap.

The USS Michigan, an American nuclear-powered submarine, arrived in the South Korean port of Busan on Tuesday for a routine visit, poised to join a group of warships including the USS Carl Vinson that is heading to the region. It came as representatives from the U.S., Japan and South Korea met in Tokyo.

“We agreed to warn North Korea to stop any additional strategic provocation and take intolerably strong punitive measures against Pyongyang if it goes ahead with such provocations,” Kim Hong-kyun, the South’s envoy for the North, told reporters following the meeting.

He said the envoys discussed ways to increase cooperation from China and Russia in getting the North to abandon its nuclear weapons program. Kim also said those present recognized Pyongyang's ally China's recent steps toward that goal.

Chinese President Xi Jinping and President Trump agreed in a phone call Monday to "strengthen coordination" to achieve the denuclearization of the Korean Peninsula, the White House said.

Later Monday, Trump said the United Nations Security Council must be prepared to impose stronger sanctions on North Korea.

"The status quo in North Korea is also unacceptable," he told 15 U.N. Security Council ambassadors at a meeting at the White House. "The council must be prepared to impose additional and stronger sanctions on North Korean nuclear and ballistic missile programs."

The entire U.S. Senate is invited to the White House on Wednesday for a briefing on threats from Pyongyang.

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