After weeks of unusually blunt military threats, the joint statement by the agency chiefs said Trump's approach "aims to pressure North Korea into dismantling its nuclear, ballistic missile and proliferation programmes by tightening economic sanctions and pursuing diplomatic measures with our allies and regional partners".
It made no specific mention of military options, though it said the US would defend itself and friends.
The unprecedented meeting in a building adjacent to the White House reflected the increased American alarm over North Korea's progress in developing a nuclear-tipped missile that could strike the US mainland.
A flurry of military activity, by North Korea and the US and its partners on and around the divided Korean Peninsula, has added to the world's sense of alert.
But the Administration's statement after briefing senators - all 100 members were invited - outlined a similar approach to the Obama Administration's focus on pressuring Pyongyang to return to long-stalled denuclearisation talks.
Trump's top national security advisers said they were "open to negotiations" with the North, though they gave no indication of when or under what circumstances.
The strategy hinges greatly on the cooperation of China, North Korea's main trading partner. "China is the key to this," said Senator John McCain, who got a preview of Trump's message at a dinner with the president this week.
Among the options are returning North Korea to the US state sponsor of terrorism blacklist, which Secretary of State Rex Tillerson said last week was under consideration.
His spokesman, Mark Toner, said that another tactic is getting nations around the world to close down North Korean embassies and consulates, or suspending them from international organisations.B ut sanctions will be the greatest tool at the Trump Administration's disposal.
Tillerson is chairing a UN Security Council meeting on Saturday designed to get nations to enforce existing penalties on North Korea and weigh new ones.
The US military started installing a controversial antimissile defence system in South Korea, triggering protests and sparking criticism that it was rushing to get the battery in place before the likely election of a president who opposes it.
The sudden and unannounced move came only six days after the US military command in South Korea secured the land to deploy the system, known as the Terminal High Altitude Area Defence, or THAAD.
Moon Jae In, a liberal candidate who has a strong lead in polls ahead of a May 9 presidential election, has promised to review South Korea's decision to host the antimissile battery.
"There's a sense in Seoul that THAAD deployment has been rushed based on the timetable of South Korea's presidential election rather than North Korea's threats," said John Delury, a professor of international relations at Yonsei University in Seoul.
"To some extent, the acceleration of THAAD deployment has 'worked,' limiting the next South Korean leader's room for maneuver," Delury said. "But there's the danger of a backlash among the South Korean public feeling like a pawn in the game of 'America First.' "
In Washington, Admiral Harry Harris, head of the Pacific Command, acknowledged that China has attempted to pressure the Government in Seoul not to deploy THAAD, and he criticised that effort.
"I find it preposterous that China would try to influence South Korea to not get a weapons system that's completely defensive against the very country that's allied with China," Harris said in testimony before the House Armed Services Committee.
Each THAAD battery includes at least six truck-mounted launchers that carry up to eight missiles each. They are designed to shoot down enemy ballistic missiles like the ones that North Korea has been launching at a steady clip.
North Korea has bolstered the case for the system by test-firing dozens of missiles over the past year, all of them capable of hitting South Korea.
- Washington Post, AP, AAP
The statement was issued by Secretary of State Rex Tillerson, Defense Secretary Jim Mattis and Director of National Intelligence Dan Coats.
