Seoul: North Korea tried and failed to test fire two powerful, new mid-range ballistic missiles on Thursday, ahead of a landmark party congress that opens next week, South Korean media reported.

The Yonhap news agency said the North made a second attempt to fire a Musudan missile in the evening, after a similar test in the early morning ended with the missile plunging to earth.

The second launch also appeared to have failed, Yonhap said, citing an unnamed official from the Joint Chiefs of Staff.

If confirmed, North Korea has now made three failed attempts in the past two weeks to test fire a Musudan, which is capable of striking US bases on the Pacific island of Guam.

The first attempt on April 15 — the birthday of founding leader Kim Il-sung — ended in what the Pentagon described as “fiery, catastrophic” failure, with the missile apparently exploding just after take-off.

South Korean military officials say the North is desperate to register a successful test flight of the Musudan ahead of the party congress, at which leader Kim Jong-un is expected to take credit for pushing the country’s nuclear weapons programme to new heights.

The failed tests come as the country is gearing up for a rare and much-hyped ruling party congress next month, at which Kim Jong-un is expected to take credit for pushing the country’s nuclear weapons programme to new heights.

There is growing concern that Pyongyang is preparing to conduct a fifth nuclear test in the run-up to the event which opens May 6.

In recent months the North has claimed a series of major technical breakthroughs in developing what it sees as the ultimate goal of its nuclear weapons programme — an intercontinental ballistic missile capable of delivering a nuclear warhead to targets across the continental United States.

The achievements trumpeted by Pyongyang have included miniaturising a nuclear warhead to fit on a missile, developing a warhead that can withstand atmospheric re-entry and building a solid-fuel missile engine.

Last Saturday, it successfully tested a submarine-launched ballistic missile (SLBM) and was promptly criticised by the

Existing UN resolutions forbid North Korea from the use of any ballistic missile-related technology, and South Korea said it would push for fresh penalties to be imposed on Pyongyang.

“The government strongly condemns this additional ballistic missile launch ... which is a clear violation of UN resolutions and an act of provocation,” the foreign ministry in Seoul said in a statement.

It said it would work with other UN members to “try to put the North’s regime under more sanctions.”

The Musudan is believed to have an estimated range of anywhere between 2,500 and 4,000 kilometres (1,550 to 2,500 miles). The lower range covers the whole of South Korea and Japan, while the upper range would include US military bases on Guam.

The missile has never been successfully flight-tested.

Two failures in swift succession will be seen as an embarrassment for the leadership, especially ahead of the party congress which is meant to celebrate the country’s achievements.

Speaking last weekend during a visit to Germany, US President Barack Obama warned that North Korea was making dangerous progress even when its efforts fell short of outright success.

“Although, more often than not, they fail in many of these tests, they gain knowledge each time,” Obama said.

“We take it very seriously, so do our allies and so does the entire world,” he added.

Anxiety has been high on the divided Korean peninsula since Pyongyang conducted its fourth nuclear test in January and a rocket launch a month later that was widely seen as a disguised ballistic missile test.

The UN Security Council responded with its toughest sanctions to date, angering the North, which has since made repeated threats of attacks targeting the South and the United States.