The Trump administrative ratcheted up its campaign against North Korea on Wednesday, summoning all 100 senators to the White House to hear top defense officials declare that defending the U.S. from a possible nuclear attack has become a top priority.

The unusual classified briefing came after the top U.S. military officer in the Pacific said the Pentagon needed to consider deploying new anti-ballistic missile systems and a defensive radar to Hawaii to protect that island state against a growing threat from North Korea.

“Kim Jong Un is clearly in a position to threaten Hawaii today, in my opinion,” Adm. Harry Harris, the chief of U.S. Pacific Command, told the House Armed Service Committee. “I have suggested that we consider putting interceptors in Hawaii that . . . defend (it) directly, and that we look at a defensive Hawaii radar.”

President Donald Trump has dispatched additional military resources to the region following North Korea’s engagement in a series of weapons tests in recent months, but aides say he hopes to use additional economic sanctions and diplomacy before resorting to military options.

Trump’s top advisers described North Korea’s pursuit of nuclear weapons as an urgent national-security threat and, for the first time, his top foreign-policy priority.

“The United States seeks stability and the peaceful denuclearization of the Korean peninsula. We remain open to negotiations towards that goal,” according to a joint statement by Secretary of State Rex Tillerson, Secretary of Defense James Mattis and Director of National Intelligence Dan Coats. “However, we remain prepared to defend ourselves and our allies.”

After the briefing, which lasted more than an hour and included a drop-in by Trump, Senate Democrats and Republicans praised the administration for saying North Korea is its top priority.

“The military is obviously planning for a number of contingencies and a number of options, as well they should, and running a full range from a more minimal military action to a far more significant military action,” Sen. Ted Cruz, R-Texas. “If there is a clear and imminent threat to the United States, our military needs to be prepared to act. I believe our military is prepared to act to keep our nation safe.”

Some senators said they hoped Trump would continue to work with Chinese President Xi Jinping on North Korea. The two had spoken as recently as Monday.

China has significant leverage with North Korea, with 80 percent of North Korea’s economy depending on ties to the nation. But defense officials say Pyongyang is unlikely to abandon its nuclear weapons program no matter how much pressure its main ally applies.

Sen. Chris Coons, D-Del., called the meeting “sobering” and said it was clear that North Korea “intends to develop nuclear weapons and the capability to deliver them.”

“It is my hope that sustained and effective diplomatic engagement by the Trump administration with China will lead China to take actions they haven’t taken previously,” he said.

US Pacific Forces Commander Admiral Harry Harris Jr., testified before the U.S. Congress on Wednesday about the threat posed by North Korea. Harris said North Korea had conducted about 60 ballistic missile tests in recent years, and it was the only country to have tested nuclear devices in this century.

North Korea conducted live-fire artillery drills this week near the city of Wonsan on the east coast, according to the country’s official media.

[RELATED: Should U.S. be preparing for a North Korean nuclear strike on the West Coast?]

“In the time I’ve been doing this, I would say that the conditions for a miscalculation by someone which could cause a military response has never been higher, and that’s primarily due to the character of the person who’s the head of North Korea right now,” said Idaho Republican Sen. Jim Risch, a member of the Senate’s Intelligence and Foreign Relations committees.

Aircraft from the USS Carl Vinson strike group, which has positioned itself in the Philippine Sea, can now reach North Korea in a two-hour flight. Harris of Pacific Command dismissed North Korea’s threats to sink the aircraft carrier and its strike group, saying, “If it flies, it will die.”

A nuclear-powered submarine, the USS Michigan, was in the area for what has been described as a routine visit while a pair of American destroyers were conducting exercises from South Korea and Japan.

A U.S. advanced missile-defense system that is being installed in South Korea will be operational in a few days, Harris said. The U.S. and South Korea agreed to deploy the $800 million system last July in a deal brokered under the now-impeached South Korean president, Park Geun-hye.

The Terminal High-Altitude Area Defense battery, which is manufactured by Lockheed Martin, can target short-, medium- and intermediate-range ballistic missiles in flight. China and Russia have opposed the defense system, saying it undermines their own security interests.

Harris said the current defense architecture “is sufficient to protect Hawaii today, but it can be overwhelmed.”

The briefing for senators had been requested by Senate Majority Leader Mitch McConnell, R-Ky. It was Trump’s decision to invite them to the White House.

“North Korea’s determined effort to field a nuclear-armed intercontinental ballistic missile threatens the United States and our allies,” McConnell said. “Kim Jong Un has, by all appearances, broken from a predictable cycle of escalation demonstrated by previous leaders, where the regime takes a provocative action, draws the U.S. into a negotiation and extracts concessions. Instead, Kim appears willing to risk the disapproval of the U.N. and our regional allies by undertaking a breakneck testing program.”

But some senators said they did not learn anything new in the briefing and they remained worried that Trump was not prepared for North Korea.

“North Korea is one of the most serious security threats that faces the United States and our allies, so we must have a sound strategy going forward,” said Sen. Kamala Harris, D-Calif. “This briefing confirmed my deep concerns about this administration’s lack of a comprehensive strategy toward North Korea.”

VERA BERGENGRUEN, SEAN COCKERHAM, ALEX DAUGHERTY AND ROB HOTAKAINEN CONTRIBUTED TO THIS REPORT.