US officials believe latest test could be for intercontinental ballistic missile as tensions soar on Korean peninsula.
North Korea has tested a rocket engine that the US believes could be part of its programme to develop an intercontinental ballistic missile, US officials said.
The test, believed to have taken place on Thursday, is the latest in a series of engine and missile trials this year and comes amid soaring tensions over Kim Jong-un’s nuclear weapons programme.
US officials, speaking anonymously to news agencies, said the engine could potentially be fitted to an intercontinental ballistic missile (ICBM).
North Korea’s state media, normally quick to publicise successful missile-related developments, did not carry any reports on the engine test.
The US, South Korea and Japan are ramping up capabilities to defend against the threat from North Korea.
On Friday, South Korean President Moon Jae-in inspected the test-launch of a mid-range missile that is being developed by its military.
"I believe in dialogue, but dialogue is possible when it’s backed by strong defence and engagement policy is possible only when we have security ability that can overwhelm the North," President Moon was quoted by his office as saying at the test site.
Moon’s office did not disclose the details of the missile being tested, but South Korea has been working to develop ballistic missiles with a range of 800km, a voluntary cap under an agreement with the US.
The US has also urged China, Pyongyang’s sole ally, to exert more economic and diplomatic pressure on North Korea to help rein in its nuclear and missile programmes.
Calling North Korea the "top security threat" to the US on Wednesday, Secretary of State Rex Tillerson said China has a "diplomatic responsibility to exert much greater economic and diplomatic pressure on the regime if they want to prevent further escalation in the region".
China’s top diplomat, Yang Jiechi, told President Donald Trump in a meeting at the White House that Beijing was willing to "maintain communication and coordination" with the US in an effort to defuse tension on the Korean peninsula, according to a statement from China’s Foreign Ministry on Friday.
Last month, the head of the US Defense Intelligence Agency told Congress that North Korea, if left unchecked, was on an "inevitable" path to obtaining a nuclear-armed missile capable of striking the US mainland.
The continental US is around 9,000km from North Korea. ICBMs have a minimum range of about 5,500km, but some are designed to travel 10,000km or farther.