North Korea has carried out another test of a rocket engine the U.S. believes could be part of its programme to develop an intercontinental ballistic missile, a United States official told Reuters on Thursday.
USA spy satellites have detected new activity at North Korea's underground nuclear test site that involve some modifications around one of the tunnel entrances to an underground test area, US officials said.
"South Korea is closely monitoring the situation under the collaboration with the United States", said Lee Eugene, vice ministry spokesperson at a regular press briefing.
Political science professor Yoo Ho-Yeol at Korea University said the test was "a carefully calibrated act of provocation ahead of the summit".
"The North has been building up missile capability for decades".
Also Friday, Moon oversaw the test-firing of a home-grown missile with a range of 800 kilometres (500 miles).
May 27 member States of the G7 warned North Korea against further nuclear tests.
It can be used to build Intercontinental ballistic missiles.
Outside observers say Pyongyang's space programme is a fig leaf for weapons tests.
The US assessed that the test, the latest in a series of engine and missile tests this year, could be for the smallest stage of an intercontinental ballistic missile rocket engine, the official said, speaking on condition of anonymity.
A midrange ballistic missile was launched from a test site in Hawaii, but an interceptor missile launched from USS John Paul Jones missed the target, the agency said.
China's top diplomat, Yang Jiechi, told Trump in a meeting at the White House that Beijing was willing to "maintain communication and coordination" with the United States in an effort to defuse tension on the Korean peninsula, according to a statement from China's Foreign Ministry on Friday.
On March 18th, North Korean media reported that leader Kim Jong-un observed a successful testing of a homegrown ICBM engine.
In April, North Korea unveiled what could be a new ICBM at a giant military parade in a show of strength.