Obama's Nuclear Security Summit opens with focus on North Korea, ISIS threats

U.S. President Barack Obama will open the second day of his final nuclear security summit in Washington, D.C. with an address to the summit's plenary session.

Terrorists will find it harder to obtain nuclear material thanks to a"key treaty" ratified by 102 nations, he said, adding thathe expected the treaty to be effective soon. "Working together, our nations have made it harder for terrorists to get their hands on nuclear material," he said.

Obama kicked off the two-day summit Thursday by meeting with the leaders of Japan and South Korea, with nuclear-defiant North Korea the focus of the talks.

Obama said he is hoping the two Asian allies will help to ensure the Korean Peninsula is free of nuclear weapons.

"We are united in our efforts to deter and defend against North Korean provocations," Obama said at a press briefing, flanked by South Korean President Park Geun-hye and Japanese Prime Minister Shinzo Abe. "We recognized that our security is linked, and that we have to meet together to meet this challenge."

• Nuclear terrorism threat will be focus of summit drawing Trudeau, world leaders to Washington
• Anti-nuclear weapon effort to be spearheaded by Canada's UN ambassador

The two-day Nuclear Security Summit in the U.S. capital, a signature event in Obama's presidency, is focused this time on how to secure nuclear and radiological material from would-be terrorists.

Among the representatives for the more than 50 countries at the summit is Canadian Prime Minister Justin Trudeau, who also met with Abe at a separate working lunch on Thursday. The heads of the international delegations attended a working dinner at the White House in the evening.

Nuclear terrorism is a shared concern that has been put into sharp relief following deadly attacks by the Islamic State, or ISIS, in the Middle East, Africa and Europe.

Fears about what ISIS could do with a nuclear weapon or a "dirty bomb" that combines radioactive dispersion with conventional explosives top the agenda at the summit. Obama described Park and Abe as stalwart allies on combating the militant group.

But North Korea's recent nuclear sabre-rattling has also lent more urgency to the discussions this week.

'Shared, urgent challenge'

North Korea fired another long-range missile in February, and the isolated state also conducted its fourth nuclear test the month before.

"The additional sanctions recently imposed on Pyongyang by the United Nations Security Council show that violations have consequences," Obama wrote in an op-ed in The Washington Post published online on the eve of the summit.

On Thursday, Park said North Korea represents a "shared, urgent challenge" among Japan, South Korea and the U.S. She warned that trilateral pressure, including even tougher sanctions on the regime, would be enforced if the provocation continues.

As worrying as the North Korean threat has been, the rise of ISIS is another development that has loomed over the talks. In 2010, when the first nuclear summit opened in Washington, the group was not the international network it is today.

Cesar Jaramillo, executive director of the Ontario-based security research organization Project Ploughshares, said any terrorist organization aspires to obtain a nuclear or radiological weapon.

Even if [a nuclear attack] is not considered to be imminent, the worst mistake the international community should make is to underestimate the threat- Cesar Jaramillo, Project Ploughshares

Last year, Belgian police seized video surveillance of a top nuclear official in Belgium from the home of a suspected ISIS conspirator with links to the killers in the November Paris attack.

"There's been intelligence about terrorists trying to acquire nuclear material, and every effort must be made by Canada and the international community to prevent that scenario," Jaramillo said.

The gravity of the prospect of nuclear terrorism is beyond dispute.

"Even if [a nuclear attack] is not considered to be imminent, the worst mistake the international community should make is to underestimate the threat because the stakes are so high," he said.

Canada to report on nuclear security efforts

Canada's prime minister has attended each of the nuclear summits since the first one in 2010. Canada, a non-nuclear weapons state, has traditionally held a strong non-proliferation and disarmament stance, and is expected to release a progress report on Friday outlining how it has spent some of the $28 million it pledged during the 2014 summit towards boosting nuclear security abroad.

Watch: Former U.S. Secretary of Defense William J. Perry imagines a nuclear scenario

Critics of the Nuclear Security Summit have said the discussions around preventing smuggling, disposing of enriched uranium and plutonium and tracking of nuclear material don't go far enough if they ignore serious consideration of complete elimination of nuclear weapons.

"The point that gets lost is it's virtually impossible to fully prevent the spread of nuclear technology in the absence of credible effort towards abolition," Jaramillo said. "There are no 'right hands' for 'wrong weapons.'"

Trudeau began the day in Washington addressing business leaders at a breakfast forum at the U.S. Chamber of Commerce, then held bilateral meetings with Abe and Japanese dignitaries, as well as Argentinian President Mauricio Macri. He is expected to attend a Thursday night working dinner hosted by Obama at the White House.

More than 15,000 nuclear warheads are estimated to be in the possession of nine countries around the world, according to the Washington-based Center for Arms Control and Non-Proliferation.

The Fissile Materials Working Group, a policy centre dedicated to combating nuclear terrorism, says that more than 1,500 kilograms of highly enriched uranium and separated plutonium have either been recovered or eliminated since the first Nuclear Security Summit in 2010.