China reiterates opposition to THAAD anti-missile system in South Korea

He went onto emphasize that it had to be, "under the right circumstances".

"I do not agree with that either because the president of the Philippines is obviously in violation of basic human rights", McCain said weighing in on the invite.

Tensions are high over Pyongyang's nuclear and missile programmes - it aims to develop a rocket that can deliver a warhead to the U.S. mainland - and threats on both sides have raised fears of conflict.

Trump's main gambit has been to encourage China to use its leverage to pressure Pyongyang - a strategy that has failed to produce results in the past.

The Trump administration has said all options, including a military strike, are on the table.

The rogue state said it will bolster its nuclear force "to the maximum" as the America builds up its military in the Korean Peninsula.

The North has been conducting missile and nuclear weapons related activities at an unprecedented rate and is believed to have made progress in developing intermediate-range and submarine-launched missiles.

As the speculation sparked security jitters, the US has sent a strike group led by aircraft carrier USS Carl Vinson and nuclear-powered submarine USS Michigan to waters off the Korean Peninsula.

The U.S. maintains no diplomatic relations with North Korea and the two countries are technically at war, as the 1950-1953 Korean conflict ended without a peace treaty.

Pompeo's visit coincided with news that the controversial USA missile defense system known as THAAD - whose deployment has angered China - was operational in South Korea.

The anti-missile system is not expected to be fully operational until the end of the year, but US and South Korean officials publicly stressed the need to speed up the deployment of the technology as tensions mounted with Pyongyang.

The Thaad battery set up in Seongju county more than 200 kilometers (125 miles) southeast of Seoul is in place and ready to operate, South Korea's defense ministry spokesman Moon Sang-gyun told reporters on Tuesday in Seoul.

The North has carried out 50 known ballistic missile tests and three nuclear experiments since leader Kim Jong-un came to power in 2011. It marked the latest fluctuation as Trump's administration struggles to articulate its policy for addressing the growing threat from North Korea's nuclear program.

But the USA leader also offered some backhanded praise for Kim, saying he had faced a formidable challenge in taking over the country at a reported age of 27 after his father's death in 2011.

That comment left the White House struggling to downplay Trump's apparent admiration.

Trump discussed the threat posed by North Korea in a telephone call with Philippines President Rodrigo Duterte, the White House said.

  • Salvatore Jensen