The timing was also interesting, coming not long after many in the United States were focused on testimony before Congress by Robert Mueller, the former special counsel, about his two-year probe into Russian election interference. And a day earlier, US National Security Adviser John Bolton left Seoul after agreeing with South Korean officials to boost cooperation to achieve North Korea's denuclearisation. South Koreans watch a TV showing a report of North Korea's latest missile launch on Thursday. Credit:AP But the missiles' relatively short flight distance also suggests the launches were not a major provocation, such as a test of a long-range missile capable of reaching the US mainland, and that North Korea doesn't appear to be pulling away from US-led diplomacy aimed at curbing its nuclear program. Loading "North Korea appears to be thinking its diplomacy with the US isn't proceeding in a way that they want. So they've fired missiles to get the table to turn in their favour," said analyst Kim Dae-young at the Korea Research Institute for National Strategy.

In recent days, North Korea has been pressuring the US and South Korea to scrap their summer-time military drills. Last week, the North said it may lift its 20-month suspension of nuclear and long-range missile tests in response to the drills. Trump has considered the weapons moratorium a major achievement in his North Korea policy. North Korea's Kim Jong-un, seen here on a TV screen in Seoul, has again fired projectiles into the sea. Credit:AP Some experts say North Korea's recent actions are an attempt to get an upper hand ahead of the possible resumption of talks. North Korea wants widespread sanctions relief so it can revive its dilapidated economy, but U.S. officials are pushing the country to take significant disarmament steps before they give up the leverage provided by the sanctions. A senior US official said the Trump administration was aware of the reports of a short-range projectile launched from North Korea. The official, who spoke on condition of anonymity, said the administration had no further comment at this time. South Korean Defence Ministry spokeswoman Choi Hyunsoo urged Pyongyang to stop acts that are "not helpful to efforts to ease military tensions on the Korean Peninsula."

If North Korea fired ballistic missiles, it could have ramifications because UN Security Council resolutions ban the North from engaging in any launch using ballistic technology. Still, the council has typically imposed fresh sanctions only when North Korea conducted long-range ballistic missile tests. "If they were ballistic missiles, they violate the UN resolutions, and I find it extremely regrettable," Japan's Defence Minister Takeshi Iwaya said. It was the first such launch since Seoul said North Korea fired three short- range missiles off its east coast in early May. Many experts said at the time that those missiles bore a strong resemblance to the Russian-designed Iskander, a short-range, nuclear-capable ballistic missile that has been in the Russian arsenal for more than a decade. Analyst Kim Dong-yub at Seoul's Institute for Far Eastern Studies said the latest North Korean missiles could be Scud-C ballistic missiles or KN-23 surface-to-surface missiles, a North Korean version of the Iskander. During a meeting at the Korean border late last month, US President Donald Trump and North Korean leader Kim Jong-un agreed to resume nuclear negotiations, which had been deadlocked since their second summit in Vietnam in February ended without an agreement because of disputes over US-led sanctions.

Loading The leaders agreed to restart nuclear talks in their hour-long meeting. During their encounter, Trump became the first US leader to set foot in North Korea while in office. "We want to get it right," Trump said of nuclear talks that had been stalled for months since a failed summit with Kim in Vietnam. "We're not looking for speed. We want to get it right." But lower-level talks between North Korea and the US have yet to restart and there's been little progress on the issue of denuclearisation since Kim and Trump's first meeting in Singapore more than a year ago. North Korea said last week that it might lift its 20-month suspension of nuclear and missile tests to protest at expected military drills between the US and South Korea that Pyongyang says are a rehearsal of an invasion.

Thursday's launches won't end that weapons test moratorium, which applies to firing long-range missiles capable of reaching the mainland US On Tuesday, North Korean state media said Kim inspected a newly built submarine and ordered officials to further bolster the country's military capabilities. The Korean Central News Agency said the submarine's operational deployment "is near at hand". After analysing photos of the submarine, experts said it most likely has three launch tubes for missiles. South Korean government documents say North Korea has about 70 submarines, but analysts say they mostly have a single launch tube. The construction of such a new submarine suggests North Korea has been increasing its military capability despite nuclear diplomacy that it began with the United States early last year. The latest launches came amid a recent flare-up of tensions on the Korean Peninsula after South Korean fighter jets fired hundreds of warning shots on Tuesday to drive away a Russian reconnaissance plane that Seoul says violated its airspace. Before that alleged intrusion, Seoul said Russian and Chinese warplanes including the reconnaissance aircraft made an extremely unusual joint entrance into South Korea's air defence identification zone, prompting South Korean military jets to scramble.