By Patricia Zengerle

WASHINGTON, April 26 (Reuters) - U.S. lawmakers want to leave briefings on North Korea on Wednesday with something many think has been absent in the Trump administration so far: a clear strategy for dealing with a major national security threat.

As a standoff escalated over the reclusive Asian nation's development of nuclear weapons and long-range ballistic missiles, President Donald Trump invited all 100 members of the Senate to attend the session with Secretary of State Rex Tillerson, Secretary of Defense Jim Mattis, Director of National Intelligence Dan Coats and Marine General Joseph Dunford, chairman of the Joint Chiefs of Staff.

While administration officials typically travel to the Capitol building to brief lawmakers on national security issues, on Wednesday the entire Senate will hop on a bus to the White House where four top officials will meet with them simultaneously. The same four officials will then go to Capitol Hill to brief the entire House at 5 p.m. EDT (2100 GMT), a senior House aide said.

"I hope and expect that it is worth the time of the trip and that we'll hear things we don't know, and that we'll come out of it better informed. We'll see," said Senator Chris Coons, a Democratic member of the Senate Foreign Relations Committee.

The meeting was set for one day after a North Korean holiday on Tuesday marking the 85th anniversary of the founding of its army. While North Korea has in the past staged nuclear or missile tests to mark the day, this year it conducted a major live-fire exercise.

It also comes as Trump tries to put the best face on his first 100 days in office, a period in which the president signed a variety of executive orders to roll back Democratic policies but has been defined by an absence of any major legislative achievements.

Lawmakers, including some of Trump's fellow Republicans, also have said the early months of his presidency have been marked by a lack of communication with Congress, partly because the administration has been slow to fill key posts and partly because Trump has been slow to develop policy positions.

Although the White House has downplayed the importance of Saturday's 100-day anniversary, Trump will mark the day with a rally in Pennsylvania.

LAYING OUT OPTIONS

White House spokesman Sean Spicer said Tillerson and the other officials would talk about the U.S. posture and activities, and that Dunford "will lay out some of the military actions" and the Pentagon's view of the situation.

Trump has discussed North Korea with U.N. ambassadors, increased the U.S. military presence in the region, and leaned on China to pressure Pyongyang. Tillerson also will chair a U.N. Security Council meeting on Friday to discuss tougher sanctions, possibly including an oil embargo and punishing Chinese companies that do business with North Korea.

North Korea denounced the U.S. actions.

"There is a saying that those who are fond of playing with fire are destined to perish in the flames. The same can be said of the U.S.," a North Korean foreign ministry spokesman said in the statement.

Members of the Senate said they hoped the administration would seek to deal with Pyongyang through diplomacy, rather than the use of force.

Republican Senator Lindsey Graham said that if Trump has "red line" on North Korea, he needs to make that clear.

"North Korea will never stop their ambitions to deliver a nuclear weapon to America until the cost of doing so is greater than the benefit. And if China and North Korea both believe that President Trump will never allow that to happen, then you have a chance to peacefully solve this," he said.

Graham and fellow Republican Senator John McCain, both defense hawks who have been Trump critics, discussed North Korea with Trump at dinner at the White House on Monday night and said they were impressed with his resolve.

(Additional reporting by Steve Holland in Washington and Michelle Nichols at the United Nations; Editing by John Walcott and Lisa Shumaker)