Graphic on North Korea’s suspected missile arsenal.

Washington (AFP)

North Korea fired another short-range missile off its east coast on Friday, South Korean officials said, as global leaders met in Washington to discuss the threat of Pyongyang’s nuclear weapons programme.

It was the latest in a series of North Korean missile launches during what has been an extended period of military tension on the Korean peninsula, triggered by Pyongyang’s fourth nuclear test on January 6.

The launch came in the middle of the two-day nuclear security summit being hosted by President Barack Obama in Washington, at which North Korea has been the focus of the US president’s talks with the leaders of China, South Korea and Japan.

The summit opened Thursday with Obama trying to forge consensus among East Asian leaders on how to respond to Pyongyang’s recent nuclear and missile tests, which have seen an escalation of tensions in the region.

In January, North Korea detonated a nuclear device and a month later launched a long-range rocket, the latest in a series of banned tests.

“We are united in our efforts to deter and defend against North Korean provocations,” Obama said after meeting Japanese Prime Minister Shinzo Abe and South Korean President Park Geun-Hye.

The leaders also discussed the deployment of the sophisticated missile system THAAD — the Theater High Altitude Area Defense System — to South Korea.

But the move has raised concerns in Beijing, which is unhappy at the prospect of the US hardware on its doorstep, fearing these will further tip the balance of power in the Pacific towards Washington.

“It in no way threatens either Chinese or Russian or other security interests in the region and will do nothing to undermine strategic stability between the United States and China,” insisted Dan Kritenbrink, Obama’s top Asia adviser.

– Shadows of Putin, Trump –

This is the fourth in a series of nuclear security summits convened at Obama’s behest and with the president leaving office next year, it may well be the last.

But it risked being overshadowed by two men who were not even there: Republican presidential frontrunner Donald Trump and Russian President Vladimir Putin.

Experts say Putin’s refusal to attend has made substantive reductions in fissile material — the vast majority of which is held by the militaries of Russia and the United States — almost impossible.

“This nuclear security summit is supposed to address all of the (fissile) stocks, but truth is that all they address really is a small proportion of civilian stocks,” Patricia Lewis, international security research director at British think tank Chatham House told AFP.

“President Obama’s initial idea was that (the summits) would address all fissile materials, but the truth is there hasn’t really been a discussion at the official level.”

Obama foreign policy advisor Ben Rhodes described the lack of Russian participation as “counterproductive,” adding that “nobody benefits from a lack or downgrading of collaboration on issues of nuclear security.”

America’s presidential election also took center stage, with questions about Trump’s suggestion that Asian allies should develop nuclear weapons.

Following the Republican frontrunner’s declaration that as president he would withdraw troops from South Korea and Japan and allow those two countries to develop nukes, Rhodes offered a scathing rebuke.

“The entire premise of American foreign policy as it relates to nuclear weapons for the last 70 years has been focused on preventing the proliferation of nuclear weapons,” he said.

“It would be catastrophic for the United States to shift its position and indicate that we somehow support the proliferation of nuclear weapons.”