All 100 U.S. senators have been invited to the White House on Wednesday for a classified briefing that will primarily concern North Korea, the administration announced Monday.
The briefing will be conducted by Defense Secretary Jim Mattis, Secretary of State Rex Tillerson, Director of National Intelligence Dan Coats and the Chairman of the Joint Chiefs of Staff, General Joe Dunford.
While lawmakers often receive classified briefings on Capitol Hill, it is rare for them to take place at the White House and for the entire Senate to be involved in one event.
During a White House lunch with ambassadors of United Nations Security Council member states on Monday, the U.S. president called unacceptable the "status quo in North Korea."
Trump said the Security Council must be prepared to impose additional and stronger sanctions on North Korea's nuclear and ballistic missile programs.
"North Korea is a big world problem, and it's a problem we have to finally solve," the president added. "People have put blindfolds on for decades, and now it's time to solve the problem."
The comments came after Trump made his latest round of separate telephone calls to the leaders of Japan, China and Germany to discuss concerns about North Korea. His most recent call was made just before meeting the ambassadors on Monday morning to German Chancellor Angela Merkel to discuss the "urgent security challenge" posed by North Korea, according to the White House.
A 30-minute call (Sunday evening U.S. time/Monday morning in Asia) between Trump and Japanese Prime Minister Shinzo Abe was meant to increase pressure on Pyongyang not to engage in further provocative actions, but was not prompted by any significant change in the situation, according to officials in Tokyo.
"We agreed to strongly demand North Korea, which is repeating its provocation, show restraint," Abe told reporters in Tokyo. "We will maintain close contact with the United States, maintain a high level of vigilance and firmly respond."
Abe also said he and Trump agreed that a larger role in dealing with Pyongyang should be played by China.
Trump subsequently spoke to Chinese President Xi Jinping about North Korea.
The Chinese president said he hopes all sides avoid doing anything to worsen the tense situation on the Korean peninsula, according to the Xinhua news agency.
Trump, in the phone call with Xi, "criticized North Korea's continued belligerence and emphasized Pyongyang's actions are destabilizing the Korean Peninsula," according to a White House readout issued Monday. "The two leaders reaffirmed the urgency of the threat posed by North Korea's missile and nuclear programs, and committed to strengthen coordination in achieving the denuclearization of the Korean Peninsula."
North Korea's continued development of ballistic missiles and its underground nuclear tests — there have been five — are "to put it mildly, a game changer," State Department spokesman Mark Toner told reporters Monday. "And it's one of the reasons why you've seen administration officials talking so candidly about our concerns and about the fact that the time for strategic patience and that policy is over."
Trump and U.S. officials have repeatedly said all options remain "on the table" to deal with further North Korean provocations.
North Korea threats
The conversations involving the president about North Korea took place as a U.S. Navy strike force, led by the aircraft carrier USS Carl Vinson, is approaching the Sea of Japan, off the east coast of the Korean peninsula.
The strike force on Monday was wrapping up a "routine" joint drill "to provide combined maritime response" with components of the Japanese Maritime Self Defense Force in the Philippines Sea "as it continued its northern transit," U.S. Navy Capt. Jeff Davis told reporters at the Pentagon.
Officials in Seoul announced earlier Monday the Vinson is also scheduled to hold a joint training exercise with South Korean naval ships.
"Consultations are under way in connection with the exercise," Ministry of National Defense spokesman Moon Sang-gyun told reporters. He provided no additional details.
The approach of the American naval carrier strike group has not gone unnoticed in Pyongyang.
"Our revolutionary forces are combat-ready to sink a nuclear-powered aircraft carrier with a single strike," read a Sunday commentary in the Rodong Sinmun, the Workers' Party newspaper.
Such threats are common from the reclusive state.
North Korea on Tuesday celebrates the anniversary of the founding of its military, a key holiday in the country.
There are concerns Pyongyang, in conjunction with the anniversary, will demonstrate a show of force by possibly firing more ballistic missiles or conducting its sixth nuclear test.
Trump has said that Xi is applying pressure on North Korea to not engage in further provocations.
It is speculated by analysts in Washington and Beijing that China is threatening to cut crude oil supplies to its impoverished neighbor should it conduct another nuclear test.
U.S. citizen detained
Meanwhile, a third U.S. citizen was detained Friday by North Korean authorities as he was about to leave the country.
Toner at the State Department told reporters he was not aware of any diplomatic access to the American.
The Pyongyang University of Science and Technology (PUST) confirmed the detention of Kim Sang-duk, who had been teaching accounting at the privately-funded school started by evangelical Christians.
"We cannot comment on anything that Mr. Kim may be alleged to have done that is not related to his teaching work on the PUST campus," the university said in a statement Sunday.
At least two other U.S. citizens are known to be held in North Korea.
The U.S. State Department said it is working with Swedish diplomats on the case.
The United States and North Korea have never had diplomatic ties. Sweden's embassy in Pyongyang represents the interests of American citizens in the country.
North Korea has a pattern of detaining and sentencing American visitors to prison in order to get high-profile visitors to go there to obtain their release.