WASHINGTON (AP) -- The Trump administration told lawmakers Wednesday it will apply economic and diplomatic pressure on North Korea to dismantle its nuclear weapons program, as an extraordinary White House briefing served to tamp down talk of military action against an unpredictable and increasingly dangerous U.S. adversary.
President Donald Trump welcomed Republican and Democratic senators before his secretary of state, defense secretary, top general and national intelligence director conducted a classified briefing. The same team also met with House members in the Capitol to outline the North's escalating nuclear capabilities and U.S. response options to what they called an "urgent national security threat."
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 programs 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 U.S. 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 U.S. mainland. A flurry of military activity, by North Korea and the U.S. and its partners on and around the divided Korean Peninsula, has added to the world's sense of alert.
While tensions have increased since Trump took office, they've escalated dramatically in recent weeks as American and other intelligence agencies suggested the North was readying for a possible nuclear test. Although such an explosion hasn't yet occurred, Trump has sent high-powered U.S. military vessels and an aircraft carrier to the region in a show of force, while the North conducted large-scale, live-fire artillery drills, witnessed by national leader Kim Jong Un, earlier this week.
On Wednesday, South Korea started installing key parts of a contentious U.S. missile defense system that also has sparked Chinese and Russian concerns.
America's Pacific forces commander, Adm. Harry Harris Jr., told Congress on Wednesday the system would be operational within days. He said any North Korean missile fired at U.S. forces would be destroyed.
"If it flies, it will die," Harris said.
The Trump administration has said all options, including a military strike, are on the table. 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 denuclearization 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 Republican Sen. John McCain of Arizona, who got a preview of Trump's message at a dinner with the president this week.
Democratic Rep. Adam Schiff of California agreed. "I think the best approach for the administration is to bring the maximum pressure to bear diplomatically on China, as well as North Korea, but otherwise to walk softly and carry a big stick," he told reporters after attending the Capitol Hill briefing Wednesday.
Among the options are returning North Korea to the U.S. state sponsor of terrorism blacklist, which Secretary of State Rex Tillerson said last week was under consideration. His spokesman, Mark Toner, said Wednesday that another tactic is getting nations around the world to close down North Korean embassies and consulates, or suspending them from international organizations.
But sanctions will be the greatest tool at the Trump administration's disposal. Tillerson is chairing a U.N. Security Council meeting Friday designed to get nations to enforce existing penalties on North Korea and weigh new ones.
Testifying before the House Armed Services Committee, Harris said he expects North Korea to soon be able to develop a long-range missile capable of striking the United States, as Kim has promised. "One of these days soon, he will succeed," Harris said.
North Korea's U.N. mission said Wednesday the nation would react to "a total war" with Washington by using nuclear weapons. It vowed victory in a "death-defying struggle against the U.S. imperialists."
Trump, like presidents before him, faces difficult options. Sanctions haven't forced Pyongyang to abandon its nuclear efforts, but a targeted U.S. attack to take out its weapons program risks a wider war along a heavily militarized border near where tens of millions of South Koreans live. The threat would extend to nearby Japan, another country North Korea regularly threatens.
China has urged restraint by both Pyongyang and Washington. In Berlin Wednesday, Foreign Minister Wang Yi said North Korea must suspend its nuclear activities, but "on the other side, the large-scale military maneuvers in Korean waters should be halted." That was a reference to U.S. and South Korean war games.
China opposes the Terminal High-Altitude Area Defense system, or THAAD, being installed in South Korea, rejecting American assurances that it will only target North Korean missiles. Russia also sees the system's powerful radars as a security threat.
In Beijing, Chinese foreign ministry spokesman Geng Shuang said THAAD would upset the region's "strategic balance." China will take "necessary measures to defend our own interests," he promised.
Associated Press writers Foster Klug, Hyung-jin Kim and Kim Tong-Hyung in Seoul; Chris Bodeen in Beijing; Richard Lardner, Matthew Lee and Lolita C. Baldor in Washington, and Edith M. Lederer at the United Nations contributed to this report.