North Korea fired what appeared to be two short-range missiles on Thursday in its second such test in less than a week, and the United States announced it had seized a North Korean cargo ship as tensions again mounted between the two countries.

US President Donald Trump said “nobody is happy” at the missile launches, which South Korea said were likely a protest by Pyongyang against Trump refusing to ease economic sanctions on the North.

The United States has given no sign of willingness to budge on sanctions and on Thursday the Justice Department announced the seizure of a North Korean cargo vessel it said was involved in the illicit shipping of coal.

Later during the day, President Donald Trump said he is studying the situation in North Korea “very seriously,” after Pyongyang welcomed a US envoy›s visit to Seoul by firing two missiles.

Trump said he knows North Korea wants to negotiate with the United States but he does not think it is ready to do so.

“The relationship continues ... I know they want to negotiate, they›re talking about negotiating. But I don›t think they›re ready to negotiate,” Trump told reporters at the White House. He said “nobody is happy” about North Korea›s latest missile launch.

North Korea has effectively pulled back from engagement with Washington since a summit between leader Kim Jong Un and Trump in February fell apart without agreement on US demands for the dismantling of Pyongyang›s nuclear programme and Kim›s demands for relief from punishing sanctions.

Less than a week ago, Kim oversaw the test-firing of multiple rockets and a missile and the latest tests coincided with a visit to the South Korean capital by US special envoy for North Korea, Stephen Biegun.

The two missiles fired on Thursday went east from the northwestern area of Kusong, South Korea›s Joint Chiefs of Staff said.

They covered distances of 420km and 270km and reached an altitude of about 50km before falling into the sea, they said.

Pentagon spokesman Lieutenant Colonel Dave Eastburn said: “We›re aware of the reports and monitoring.”

“North Korea seemed to be discontented it could not reach a deal in Hanoi,” South Korea›s President Moon Jae-in told South Korean broadcaster KBS, referring to the summit in Hanoi with Trump.

South Korea›s Moon said that even if the missiles fired on Thursday were short range, they could still violate UN resolutions barring North Korea from developing its ballistic missile force.

Even so, Moon said he saw the tests as a sign that North Korea wanted to negotiate, and said he planned to push for a fourth inter-Korean summit with Kim.

US Secretary of State Mike Pompeo, who earlier cut short a European trip to return to Washington for meetings on Iran, was also due to have discussions on North Korea after learning of the launches, a senior US State Department official said.

Pompeo was due to meet on Thursday with Japan›s Chief Cabinet Secretary Yoshihide Suga, who is expected to raise Japanese Prime Minister Shinzo Abe›s hopes to set up a summit with Kim.

Analysts said it was too soon to say exactly what kind of missiles were involved in the latest launches, but the range would probably exceed that of most of the rockets North Korea fired on Saturday from its east coast into the ocean.

“North Korea has returned to its classic escalation tactics from before,” said Yang Uk, a senior research fellow at the Korea Defence and Security Forum. “I believe they will keep escalating by using what appear to be short-range missiles, something that will not cause the US to react right away.”

Harry Kazianis, of Washington›s Center for the National Interest think tank, said the new launches could only worsen tensions.

“While this recent launch of short-range missiles does not violate Pyongyang’s promise to halt longer-range tests, North Korea has now made it clear it will not halt developing other parts of its military capabilities that threaten the region,” he said.

“Kim’s goal, beyond ensuring his weapons programmes are becoming more powerful, is quite clear: to show America and its allies that if they aren’t willing to compromise on the terms of denuclearisation.”

Reuters