Trump administration says it aims to push North Korea into dismantling its nuclear and missile programmes through tougher international sanctions and diplomatic pressure.
The United States pledged to step up sanctions to force North Korea to resume dialogue over its nuclear programme, but said it was not looking to bring Kim Jong-Un's regime to its knees.
After briefing senators at the White House, top US officials said President Donald Trump also aimed to pursue diplomatic measures with allies and regional partners.
"We are engaging responsible members of the international community to increase pressure on (North Korea) in order to convince the regime to de-escalate and return to the path of dialogue," read a statement from Pentagon chief Jim Mattis, Secretary of State Rex Tillerson and Director of National Intelligence Dan Coats.
The US stance, which appeared to signal a willingness to exhaust non-military options in spite of repeated warnings that "all options are on the table," came in a statement following the briefing.
The statement described North Korea as "an urgent national security threat and top foreign policy priority".
TRT World's Lorna Shaddick reports from New York.
Lawmakers seek clear strategy
Trump has vowed to prevent North Korea from being able to hit the United States with a nuclear missile, a capability experts say it could have some time after 2020.
"The United States seeks stability and the peaceful denuclearisation of the Korean peninsula. We remain open to negotiations towards that goal. However, we remain prepared to defend ourselves and our allies," said the report.
US lawmakers have been seeking a clear White House strategy following repeated North Korean missile tests and fears that it could conduct a sixth nuclear bomb test.
Democratic Senator Christopher Coons told reporters after the White House briefing that military options were discussed.
"It was a sobering briefing in which it was clear just how much thought and planning was going into preparing military options, if called for, and a diplomatic strategy that strikes me as clear-eyed and well proportioned," Coons said.
Tillerson will chair a ministerial meeting of the UN Security Council on Friday that is expected to discuss tougher steps, which US officials say could include an oil embargo, banning North Korea's airline, intercepting cargo ships and punishing Chinese and other foreign banks doing business with Pyongyang.
China's full support needed
Earlier on Wednesday, North Korea's foreign ministry called US attempts to make Pyongyang give up its nuclear weapons through military threats and sanctions "a wild dream" and like "sweeping the sea with a broom".
The administration is hoping for greater Chinese cooperation after a summit between President Xi Jinping and Trump last month, and a senior White House official said Beijing now appeared to acknowledge North Korea as a threat to China too.
China objects to North Korea's weapons development, and has called repeatedly for a return to international negotiations.
However, China has been angered by US deployment of the Terminal High Altitude Area Defense (THAAD) missile defense system in South Korea, complaining that its radar can see deep into China and undermines its security.
The frontrunner in South Korea's May 9 presidential election has called for a delay in THAAD deployment, saying the new administration should make a decision after gathering public opinion and more talks with Washington.
North Korea has vowed to strike the United States and its Asian allies at the first sign of any attack on its territory.
In a show of force, the United States is sending the USS Carl Vinson aircraft carrier group to waters off the Korean peninsula, where it will join the USS Michigan, a nuclear submarine that docked in South Korea on Tuesday.
The carrier is in the Philippine Sea, within two hours' striking distance of North Korea if need be.