President Trump and Chinese President Xi Jinping pause April 7 for photographs at Mar-a-Lago in Palm Beach, Fla. Trump spoke by phone with Xi and the Japanese president Monday. (Alex Brandon/AP)

The White House announced Monday that it would host an unusual private briefing on North Korea for the entire Senate on Wednesday, and President Trump spoke with his counterparts in China and Japan.

The flurry of activity comes ahead of a key anniversary Tuesday and as Washington steps up pressure on the North.

Just days after the nation marked the birthday of founder Kim Il Sung with a massive military parade and missile test, there are concerns that North Korea could stage a provocative missile or nuclear test Tuesday, the anniversary of its military’s founding.

Trump discussed the situation with Chinese President Xi Jinping, who urged Washington and Pyongyang to meet each other halfway, and with Japanese Prime Minister Shinzo Abe, who demanded that North Korea stop repeating “dangerously provocative actions.”

The return of a U.S. aircraft carrier strike group to the region could also reignite tensions, especially if it is accompanied by another round of punchy rhetoric from either Pyongyang or Washington.

Speaking to the U.N. ambassadors from the Security Council member countries on Monday, Trump said “the status quo in North Korea is also unacceptable,” and that the U.N. council must be prepared to impose additional and stronger sanctions on the country.

White House press secretary Sean Spicer told reporters that all senators would be briefed on North Korea on Wednesday by several senior administration officials, including Secretary of State Rex Tillerson and Defense Secretary Jim Mattis.

Spicer said the briefing would be held at the White House. Such briefings usually take place in a secure location on Capitol Hill, where there is more room to handle such a large group.

Past administrations have often held briefings for smaller groups of about two dozen or fewer lawmakers in the White House Situation Room. But they have traditionally sent high-level aides to Capitol Hill to hold discussions with larger groups in secure underground locations.

A senior Trump administration official said the meeting with senators will take place in the auditorium at the Eisenhower Executive Office Building, the building next to the White House that houses most of the National Security Council. The auditorium will be temporarily turned into a “sensitive compartmented information facility,” or SCIF, which is the term for a room where sensitive national security information can be shared, the official said.

Meanwhile, in Beijing, the possibility of another missile test by North Korea is leading to mounting frustration with Pyongyang and an increasingly obvious deterioration in relations with its neighbor.

(White House)

On Monday, the Global Times newspaper said that if North Korea stages a sixth nuclear test, Beijing would “undoubtedly support” the United Nations in adopting tougher sanctions against the regime, including an embargo on oil exports.

China says it has already suspended all coal imports from North Korea, and although several North Korean ships, thought to be laden with coal, have been seen at Chinese ports recently, there are no indications that they have been allowed to unload their cargoes.

The prospect of stiffer sanctions has already had an impact on daily life in Pyongyang: The NK News website reported Saturday that gasoline prices in the capital had nearly doubled in recent days, with residents lining up at gas stations; some stations were closed and others were selling fuel only to foreign organizations and diplomats.

The regime’s Korean Central News Agency (KCNA) criticized China — without naming it — for “dancing to the tune” of the United States on Friday. The Global Times, whose views do not necessarily reflect official policy, responded in an editorial that such a broadside “will not have any effect apart from further isolating Pyongyang itself.”

Such public sniping is rare between the two allies, who fought side by side during the Korean War and have since emphasized their close bond and unbreakable friendship.

In his phone call with Trump, China’s Xi called for restraint from both Washington and Pyongyang, the Foreign Ministry said in a statement, but he also stressed that China “resolutely opposes activities that violate U.N. Security Council resolutions” and is willing to work with the United States and other countries to keep the peace.

Japan’s Abe had a 30-minute call with Trump to discuss North Korea, whose actions he called an “extremely serious threat” to international society and to his country.

“I told him we highly value President Trump’s attitude to show all options are on the table with his words and actions,” Abe told reporters in Tokyo. “We completely agreed to strongly demand that North Korea, which continues to carry out dangerous provocative actions, exercise self-restraint.” 

A White House statement Monday said that Trump and Xi “reaffirmed the urgency of the threat posed by North Korea’s missile and nuclear programs” and pledged to “strengthen coordination in achieving the denuclearization of the Korean Peninsula.”

The White House was less clear in describing Trump’s call with Abe, saying the leaders “addressed a range of regional and global issues of mutual concern.”

Naval destroyers from Japan’s Maritime Self-Defense Force started drills with the carrier strike group led by the USS Carl Vinson in the Philippine Sea on Sunday, and the South Korean navy is expected to do the same as the group approaches the Korean Peninsula.

An American guided-missile submarine, the USS Michigan, arrived at the South Korean port of Busan Tuesday, in what the U.S. Navy described as a “routine visit.” Rear Adm. Brad Cooper, commander of U.S. Naval Forces Korea, described the visit as “yet another example of the steadfast [South Korean] and U.S. naval partnership.”

In Asia last week, Vice President Pence said that “all options are on the table” for dealing with North Korea and its provocations, although experts say a military strike remains unlikely.

North Korea responded by saying that the Trump administration was “spouting a load of rubbish” with its calls for “browbeating” Pyongyang and its deployment of the carrier group. “Such intimidation and blackmail can never frighten” North Korea, the Foreign Ministry said, according to a report carried by KCNA.

Another state media outlet was even more defiant, threatening to sink the Carl Vinson, which it compared to a “gross animal,” according to Reuters.

“Our revolutionary forces are combat-ready to sink a U.S. nuclear-powered aircraft carrier with a single strike,” the Rodong Sinmun, the newspaper of the ruling Workers’ Party, said in a commentary.

There are continued signs of activity at North Korea’s main nuclear test site, at Punggye-ri in the northeast of the country. The latest satellite images show trailers and mining carts at the site, according to the 38 North website, although activity does not always mean that the North Koreans are planning a test.

China’s Defense Ministry denied media reports last week that it had put its troops on “high alert” near the North Korean border, saying it was merely conducting “normal training.”

But Beijing is not only frustrated with Pyongyang.

It also blames the United States for forcing the regime into a corner, with the George W. Bush administration backing out of negotiations and naming North Korea as part of an “axis of evil” in 2002. The toppling of Iraq’s Saddam Hussein and Libya’s Moammar Gaddafi also helped convince Pyongyang’s rulers that abandoning their nuclear program would lead to their overthrow, experts say.

The Global Times said Trump had initially labeled President Barack Obama’s policies as mistaken but then followed the same line.  

“Washington should also reflect on its wrongdoing,” it wrote. “Trump won’t reach the right destination if he only changes a pair of shoes while continuing along the same old path.”

Denyer reported from Beijing and Fifield reported from Tokyo. Philip Rucker and Ed O’Keefe in Washington contributed to this report.