U.S. President Donald Trump on Wednesday praised North Korean leader Kim Jong Un for a "wise" decision not to fire missiles towards the U.S. Pacific territory of Guam, which has eased escalating tension between the two countries.

Reclusive North Korea has made no secret of its plan to develop a nuclear-tipped missile capable of hitting the United States to counter what it perceives as constant U.S. threats of invasion.

Trump warned North Korea last week it would face "fire and fury" if it threatened the United States, prompting North Korea to say it was considering plans to fire missiles toward Guam.

But North Korean media reported on Tuesday that Kim had delayed the decision while he waited to see what the United States did next.

"Kim Jong Un of North Korea made a very wise and well reasoned decision," Trump wrote on Twitter.

"The alternative would have been both catastrophic and unacceptable!"

North Korea's threat to fire into the sea near Guam had prompted Trump to say earlier that the U.S. military was "locked and loaded" if North Korea acted unwisely.

North Korea has long ignored warnings from the West and from its lone major ally, China, to halt its nuclear and missile tests which it conducts in defiance of U.N. Security Council resolutions.

U.N. Secretary-General Antonio Guterres said on Wednesday it was time to "dial down rhetoric and dial up diplomacy" on North Korea and that he had told Russia, Japan, the United States, China and North and South Korea that he was available to help broker talks.

"My good offices are always available – and I conveyed this message yesterday to the representatives of the six-party talks," Guterres told reporters. "The solution to this crisis must be political. The potential consequences of military action are too horrific to even contemplate."

The United States has been hoping China can press the North to rein in its weapons programs, something the top U.S. general reiterated in talks in Beijing this week.

Chairman of the U.S. Joint Chiefs of Staff Joseph Dunford told Fang Fenghui, chief of the Joint Staff Department of the People's Liberation Army, that North Korea's weapons programs threatened the entire international community, including China.

"He emphasised that the U.S. and China have the same goal - a denuclearised Korean peninsula achieved through peaceful means ... North Korean actions threaten the economic and military security of China," a U.S. military spokesman said in a statement.

"In the interest of regional stability, he said the U.S. views with growing urgency the need for China to increase pressure on the North Korean regime," the spokesman said.

'SOLIDARITY AND RESOLVE'

China has repeatedly called for all sides to exercise restraint and remain calm, and while it has signed up for tough U.N. sanctions on North Korea, it says the key to a resolution lies in Washington and Pyongyang talking to each other, rather than expecting China to do all the work.

German Foreign Minister Sigmar Gabriel said while everyone was concerned about the situation, Chinese pressure on North Korea had made him more upbeat.

"Since yesterday we are a bit more optimistic; I think that above all Chinese pressure contributed to the statements from North Korea about definitely putting aside these ideas of firing a missile," Gabriel said in Berlin. He said he had spoken with his counterparts in China, the United States and South Korea in recent days.

"All options" are on the table with regards to North Korea, U.S. Vice President Mike Pence told reporters in Chile on Wednesday. He called on Latin American nations to break ties with Pyongyang.

Japan conducted air manoeuvres with U.S. bombers southwest of the Korean peninsula on Wednesday involving two U.S. Air Force B-1B Lancer bombers flying from Andersen Air Force Base on Guam and two Japanese F-15 jet fighters, Japan's Air Self Defence Force said in a news release.

"These training flights with Japan demonstrate the solidarity and resolve we share with our allies to preserve peace and security in the Indo-Asia-Pacific," the U.S. Air Force said.

The U.S. aircraft have flown several sorties in East Asia in recent weeks. In addition to air drills with Japanese fighters, the bombers have also exercised with South Korean aircraft.

North Korea regards the U.S. exercises with South Korea and Japan as preparations for invasion. The exercises also upset China, which says they do nothing to ease tension.