US President Donald Trump said that "nobody's happy" after North Korea raised the pressure over the future of their deadlocked nuclear negotiations by launching two short-range missiles.
Trump's second summit with North Korean leader Kim Jong Un in Hanoi in February broke up without an agreement or even a joint statement as the two failed to reach a deal on what Pyongyang would be willing to give up in exchange for relief from sanctions imposed over its banned nuclear weapons and ballistic missile programmes.
Since then Kim has accused Washington of acting in "bad faith" and given it until the end of the year to change its approach.
In what South Korea President Moon Jae-in termed an "element of protest", the North "fired what appeared to be two short-range missiles" on Thursday, Seoul's Joint Chiefs of Staff (JCS) said in a statement.
They were launched from Kusong in North Pyongan province, it said, and flew eastwards for 270 and 420 kilometres (170 and 260 miles) across the North.
It was Pyongyang's second such move in less than a week, after having not launched a missile since November 2017, shortly before a rapid diplomatic thaw eased high tensions on the peninsula and paved the way for the historic first Kim-Trump summit in Singapore last June.
At a White House event, Trump said US authorities were looking "very seriously" at the launch of the "short-range missiles".
"Nobody's happy about it," he told reporters.
"We'll see what happens," he added. "I know they want to negotiate, they're talking about negotiating. But I don't think they are ready to negotiate."
Thursday's launches came hours after the US Special Representative on North Korea, Stephen Biegun, arrived in Seoul for talks with South Korean officials, in his first visit since the Hanoi summit.
- 'Peace and security' -
North Korea's Rodong Sinmun newspaper, the mouthpiece of the ruling party, devoted its entire front page and half of page two to the launch on Friday, with 16 pictures, the main one of Kim watching the launch from a camouflaged shelter.
It was a "long-range strike" drill, the official Korean Central News Agency said, without specifying what kind of weapon was fired and avoiding the words missile, rocket or projectile.
Thursday's missile firing came after North Korea carried out a military drill and fired multiple projectiles on Saturday, with at least one believed to be a short-range missile.
And in a potential indication of more launches to come, KCNA said that Kim "set forth important tasks for further increasing the strike ability of the defence units".
"The genuine peace and security of the country are guaranteed only by the strong physical force capable of defending its sovereignty," it cited him as saying.
The pictures of the two launches released by the North appeared similar, and experts said at least one short-range ballistic missile was involved on Saturday.
A report on the respected 38 North website said debris left by the launch suggested it was a "direct import" of a Russian-produced Iskander -- a single-stage, solid-fuel missile.
If North Korea had imported Iskanders from Russia, the report added, "it has an existing capacity to deliver warheads to targets in South Korea with great precision".
Pyongyang, Seoul and Washington had all refrained from explicitly calling Saturday's launch a missile -- the South used the term "projectile" -- which could jeopardise the ongoing diplomacy if it violated UN Security Council bans on ballistic technology as well as Kim's announcement of an end to long-range missile tests.
But Japanese defence minister Takeshi Iwaya said Friday that Tokyo had "reached the conclusion" the latest launches were short-range ballistic missiles.
"Launching of ballistic missiles is a clear violation of relevant UN Security Council resolutions," he told reporters.
- 'Highly displeased' -
Pyongyang's latest move "is a pressuring action to steer the nuclear talks in a direction it desires", South Korea's President Moon said in an interview marking his first two years in office.
"It appears the North is highly displeased that the Hanoi summit ended without agreement," he added, but warned that the launch "could make negotiations more difficult".
A summit between Moon and Kim a year ago was instrumental in lowering the temperature, but since the Hanoi summit, the North has blamed Seoul for siding with Washington, leaving inter-Korean relations in limbo.
In New York, federal authorities said the US had taken possession of a North Korean freighter seized a year ago by Indonesia on grounds of violating UN sanctions.
The officials said Wise Honest -- an 18,000-ton, single hull bulk carrier -- had exported high-grade coal and brought back machinery to the impoverished and reclusive country.