North Korea has fired two short-range ballistic missiles off its east coast, South Korea’s military said, less than a week after Pyongyang’s first weapons tests in more than two months.

Observers say the launches were aimed at ramping up pressure on the United States to make concessions as the two countries are struggling to resume diplomacy on North Korea’s nuclear weapons programme.

South Korea’s Joint Chiefs of Staff said in a statement the missiles were launched from the town of Wonsan, a regular launch site on the North’s eastern coast.

It said both missiles were believed to have flown about 250km (155 miles) at a maximum altitude of 30km (19 miles) and that South Korean and US militaries were trying to find more details of the launches.

“The North’s repeated missile launches are not helpful to an effort to ease tensions on the Korean Peninsula and we urge (North Korea) to stop this kind of behaviour,” a Joint Chiefs of Staff statement said.

Japanese prime minister Shinzo Abe briefly told reporters the launches were “no threat to Japanese national security”.

Six days earlier, North Korea fired two short-range ballistic missiles that Seoul officials say flew 600km (370 miles) before landing at sea.

The North Korean government shows a test of a missile launch in North Korea from last week
The North Korean government shows a test of a missile launch in North Korea from last week (Korean Central News Agency/Korea News Service via AP)

UN Security Council resolutions ban North Korea from using ballistic technology in any weapons launches.

But it is unlikely that the nation, already under 11 rounds of UN sanctions, will be hit with fresh punitive measures.

Past sanctions were imposed only when the North conducted long-range ballistic launches.

Japan’s defence minister Takeshi Iwaya told reporters on Wednesday that the launched objects did not reach the Japanese exclusive economic zone.

Referring to the previous launches, Mr Iwaya said, “It is extremely regrettable that North Korea continues firing the missiles that violates the UN resolutions.”

North Korea’s state media said last week’s tests were supervised by Kim Jong Un and were designed to deliver a “solemn warning” to South Korea over its purchase of high-tech US-made fighter jets and planned military drills that Pyongyang sees as an invasion rehearsal.

Earlier last week, Mr Kim also visited a newly built submarine and expressed his satisfaction with its weapons system. North Korea said its deployment was “near at hand”.

Wednesday’s launches came hours after a senior US official said President Donald Trump has sent mementos from his brief visit to an inter-Korean border town late last month to Mr Kim.

The official said a top staffer from the National Security Council hand-delivered photographs from the June Trump-Kim meeting at the Korean demilitarised zone (DMZ) to a North Korean official last week.

The DMZ meeting was the third summit between Mr Trump and Mr Kim.

At their second meeting, in Vietnam, Mr Trump rejected Mr Kim’s demand for widespread sanctions relief in return for dismantling his main nuclear complex, a partial disarmament step.

During the DMZ meeting, Mr Trump and Mr Kim agreed to resume the nuclear diplomacy in coming weeks, but there has not been any known meeting between the countries.

Speaking to reporters accompanying him to an Asian security forum in Thailand, US Secretary of State Mike Pompeo said he was very hopeful for a quick resumption in the nuclear talks.

He said he was waiting to see if North Korea’s foreign minister comes to the meeting in Bangkok and is confident the two will see each other if he does.

Some experts say North Korea wants a US promise to ease sanctions, accept a slow, step-by-step disarmament process by North Korea or make other concessions once the diplomacy restarts.

Despite a recent lack of progress in nuclear diplomacy, both Mr Trump and Mr Kim have said they have maintained good relations with each other.

After Thursday’s missile launches, Mr Trump tried to downplay the significance of the tests, saying that “short-range” was the most important word.

He said North Korea fired “standard” missiles many countries possess.

South Korea’s military said the flight data of the weapon launched last week showed similarities to the Russian-made Iskander, a short-range, nuclear-capable missile. A North Korean version could likely reach all of South Korea — and the 28,500 US forces stationed there — and would be extremely hard to intercept.

After entering talks with the US, North Korea has suspended nuclear and long-range missile tests, and Mr Trump views that as a proof that his North Korea policy is working well and has eased the danger of a war with the North.