Senators arrive at White House for classified North Korea threat briefing

North Korea's nuclear and missile threat is perhaps the most serious security challenge confronting U.S. President Donald Trump. He said China would take measures against the move, which would "disrupt the regional strategic balance and further aggravate tensions on the peninsula".

The release specifically cites US allies South Korea and Japan as partners in the effort to reel in North Korea.

Chinese officials, who have been calling for the programme aimed at protecting Seoul from North Korea's nuclear threat to be scaled back, denied any involvement. With the THAAD deployment causing the overall attitude toward South Korea in Chinese society to sour, there are also concerns about the long-term impact on the business of South Korean companies inside China.

The top United States commander in the Asia-Pacific, Admiral Harry Harris, says he's encouraged by signals from China that it would help address North Korea's threatening behaviour, but cautions "it's early days".

The US is installing the THAAD system in South Korea.

Admiral Harry Harris, who heads the US Pacific Command, said in Washington this week the US Carl Vinson strike group was in the Philippine Sea just east of Okinawa, "in striking range and power projection range of North Korea if called upon to do that".

The United States said in March that it had started deploying the THAAD system in South Korea to help protect against threats from North Korea.

Foreign Ministry says sudden delivery of components, "will aggravate regional tensions and undermine China's strategic security interests " As the deployment of the THAAD missile defense system in South Korea moves forward with the unexpected delivery of key THAAD components to the golf course in Seongju, North Gyeongsang Province on April. 26, China is protesting loudly.

Tillerson will chair a ministerial meeting of the U.N. Security Council on Friday that is expected to discuss tougher sanctions, which USA 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.

Coons said a resolution of the "very difficult" North Korea problem would require "persistent engaged allocation of diplomatic and military resources and effort".

China has long promoted dialogue to resolve the "Korean nuclear issue" as North Korea has repeatedly threatened to destroy the United States which in turn has warned that "all options are on the table" in ending North Korean provocations.

He said any North Korean missile fired at USA forces would be destroyed.

At the briefing, Trump asserted that a different course on North Korea diplomacy would stem from his ability to "get things done", according to a Senate aide.

Nationally, opponents argue THAAD is ineffective against the North's short-range missile and massive artillery arsenal that could target half of the nation's population of 50 million living in Seoul and other regions close to the inter-Korean border.

While the administration has said military strikes remain an option, officials have stressed tougher sanctions as the key strategy given the risks of massive North Korean retaliation - essentially representing a continuation of the policy of former President Barack Obama's administration, which failed to slow Pyongyang's weapons programs. He said China opposes "war and unrest" on the Korean Peninsula.

Geng said "China will firmly be taking necessary measures to defend our own interests" but offered no details. The executive mansion is an extremely rare venue for such an event.

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.