The Washington Post's David Nakamura explains why the White House is hosting the entire Senate for a meeting on North Korea on April 26. (Sarah Parnass/The Washington Post)

The White House announced Monday that it would host an unusual private briefing on North Korea for the entire Senate, prompting questions from lawmakers about whether the Trump administration intends to use the event as a photo op ahead of its 100-day mark.

Press secretary Sean Spicer told reporters that the lawmakers would be briefed Wednesday by several senior administration officials, including Secretary of State Rex Tillerson and Defense Secretary Jim Mattis. He emphasized that the meeting plan had been convened by Senate leadership and that the White House was serving “as the location.”

Yet the White House setting perplexed lawmakers who have grown accustomed to such briefings taking 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.

Such facilities are configured to withstand eavesdropping or other technical snooping.

White House press secretary Sean Spicer on April 24 announced that the White House will host a meeting on North Korea for all senators. (The White House)

David Popp, a spokesman for Senate Majority Leader Mitch McConnell (R-Ky.), explained that "the president offered to host the meeting, and the majority leader agreed."

Other Senate leadership staffers signaled that most, if not all, senators in both parties are expected to attend the White House briefing.

But the unusual location left many staffers scratching their heads.

In recent years during debates surrounding Syria's civil war, terrorist attacks in Europe and the FBI’s investigation into Russian interference in U.S. elections, Cabinet secretaries and senior law enforcement officials have traveled to Capitol Hill to brief lawmakers.

“These briefings are always, always, always done in the SCIF up here,” one Senate aide, who was not authorized to talk on the record and so spoke on the condition of anonymity, said Monday. “Does it mean classified information is going to be shared in an unsecured setting? Or that we’re not hearing about classified material?”

Another senior aide, who also spoke on the condition of anonymity, said it was President Trump’s idea to hold the meeting at the White House.

“I heard this came from Trump himself, that in a nutshell he said, ‘Why don’t we have them up here instead?’ ” the aide said.

The senior administration official confirmed that Trump offered the White House complex as a location and that McConnell accepted.

Kim Jong Un has tested nuclear weapons and ballistic missiles at an unprecedented rate since he came into power. Yet, the country is under some of the toughest sanctions ever. This is how the regime is able to funnel billions of dollars into its nuclear program. (Jason Aldag/The Washington Post)

Congressional staffers suggested that the briefing’s proximity to Trump would make it easy for him to “drop by” and perhaps take over the briefing.

The image of senators meeting with Trump at the White House on a top national security concern could be touted by the White House as a key moment in the run-up to Trump’s 100th day in office — a milestone that the president has mocked in recent days but that his administration is working aggressively to promote.

At a lunch at the White House, April 24, President Trump told ambassadors from countries on the U.N. Security Council that they must be prepared to impose new sanctions on North Korea amid escalating tensions over its missile and nuclear programs. (Reuters)

Trump has sought to strike a tougher tone on North Korea in the wake of Pyongyang's latest weapons tests, which included a failed missile test this month. On Monday, U.N. Ambassador Nikki Haley hosted counterparts from the U.N. Security Council in Washington to discuss the security situation in Syria and North Korea, and Trump met with them and posed for a picture with the group, officials said.

“The status quo in North Korea is also unacceptable,” Trump told the U.N. ambassadors. “The council must be prepared to impose additional and stronger sanctions on North Korean nuclear and ballistic missile programs.”