SEOUL/WASHINGTON — 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 said 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 launches, but still appeared to hold the door open for more talks with North Korea. South Korea said the tests were worrisome and unhelpful and likely a protest against Trump refusing to ease economic sanctions on North Korea at a failed summit in Hanoi in February.

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

North Korea has effectively pulled back from engagement with Washington since the Hanoi meeting between its leader Kim Jong Un and Trump collapsed without agreement on U.S. demands for the dismantling of Pyongyang’s nuclear program and Kim’s demands for relief from punishing sanctions.

“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.

Acting US Defense Secretary Patrick Shanahan said the United States would continue to focus on diplomatic efforts with North Korea.

“We’re going to stick to our diplomacy and as you all know we haven’t changed our operations or our posture and we’ll continue to generate the readiness we need in case diplomacy fails,” he told reporters outside the Pentagon.

Trump has held up a freeze in missile testing since 2017 as a sign of progress in his talks with North Korea after exchanges of fiery rhetoric two years ago raised fears of war.

North Korea formally announced a freeze in intercontinental ballistic missile (ICBM) and nuclear bomb tests in April last year and Trump stressed that the missiles fired were not of a kind that could threaten the United States.

“We’re looking at it very seriously right now. They were smaller missiles, they were short-range missiles,” he said. “Nobody’s happy about it but we’re taking a good look and we’ll see.”

North Korea’s official KCNA news agency said Kim oversaw the army “strike drill,” and said he noted that “genuine peace and security of the country are guaranteed only by the strong physical force capable of defending its sovereignty.”

White House chief of staff Mick Mulvaney played down the tests, telling CBS News the “supposed provocation” was “very minor.”

“These missiles, whatever they were, whatever you want to call them, they were very small. And not aimed at Japan, not aimed at Guam, they were aimed up the North Korean coast. So it was a very non-provocative provocation, if there is such a thing.”

He said the relationship between Kim Jong Un and Trump remained good and he was confident there would be more talks with North Korea. “We want additional talks,” he said.

Asked if the US side wanted another summit, he said: “Eventually? Yeah, I think we do,” while adding that at the last summit the North Koreans “were not really willing to negotiate.’

“They gave us an offer — you know, a take it or leave it offer — five different times. And we couldn’t take it, so we had to leave.”

UN Secretary-General Antonio Guterres urged all parties to continue talks toward denuclearization, warning that Pyongyang’s latest action “serves only to increase tensions,” UN spokesman Farhan Haq said.

Less than a week ago, Kim oversaw the test-firing of multiple rockets and a missile. That was North Korea’s first test of a ballistic missile since an ICBM launch in November 2017 that it said was capable of delivering a warhead anywhere in the United States.

The two missiles fired on Thursday flew east from the northwestern area of Kusong, South Korea’s Joint Chiefs of Staff said. They covered distances of 420 km (260 miles) and 270 km (168 miles) and reached an altitude of about 50 km (30 miles) before falling into the sea, they said.

South Korea’s President Moon Jae-in, who has strongly advocated engagement with North Korea, said that even if the missiles were short range, they could still violate UN resolutions barring North Korea from developing ballistic missiles.

“North Korea seemed to be discontented it could not reach a deal in Hanoi,” he told South Korean broadcaster KBS, while adding that he saw the tests as a sign that North Korea wanted to negotiate and that he planned to push for a fourth inter-Korean summit with Kim.

US Secretary of State Mike 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 for a summit with Kim.

Trump and Pompeo have brushed aside Kim’s demand for Washington to show more flexibility in talks by the end of the year.

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 Defense 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 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 programs 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 denuclearization, that Pyongyang will indeed go its own way, with missile launches once again becoming the new norm.”

The latest tests coincided with a visit to the South Korean capital by US special envoy for North Korea Stephen Biegun.

North Korea lashed out at the United States and South Korea this week, saying last weekend’s launches were “regular and self-defensive.” It criticized Seoul and Washington for carrying out military drills.

North Korea has repeatedly denounced US-led sanctions aimed at pressing it to give up its nuclear weapons and the mood will not have been lightened by the ship seizure announced on Thursday, the first by the United States of a North Korean cargo vessel for violating sanctions. — Reuters