Top Trump administration officials are set to hold a rare briefing at the White House for the entire US Senate on the situation in North Korea, senior Senate aides say.
All 100 senators have been asked to the White House for the briefing by Secretary of State Rex Tillerson, Secretary of Defense Jim Mattis, Director of National Intelligence Dan Coats and General Joseph Dunford, chairman of the Joint Chiefs of Staff, the aides said on Monday.
While top administration officials routinely travel to Capitol Hill to address members of Congress on foreign policy and national security matters, it is unusual for the entire 100-member Senate to go to such an event at the White House, and for those four top officials to be involved.
US officials have expressed mounting concern over North Korea's nuclear and missile tests, and its threats to attack the United States and its Asian allies.
President Donald Trump criticised North Korea's "continued belligerence" and said its actions were destabilising during a telephone call with Chinese President Xi Jinping on Sunday, the White House said.
House aides said they were working with the White House to set a similar briefing for members of the House of Representatives.
