The Latest: Obama welcomes strong China despite tensions

WASHINGTON (AP) - The Latest on the nuclear security summit convened by President Barack Obama in Washington (all times local):

2:30 p.m.

President Barack Obama says the U.S. welcomes a peaceful, strong China despite tensions with the Asian powerhouse over its building in the disputed South China Sea.

Obama's meeting with Chinese President Xi Jinping (shee jihn-peeng) on the sidelines of a two-day nuclear security summit follows Obama's earlier three-way meeting with the leaders of Japan and South Korea.

China recently agreed to tough U.N. sanctions against its traditional ally, North Korea, over North Korean missile tests. Obama will urge China to begin implementing the sanctions.

Obama addressed reporters as the meeting began. He says he and Xi will discuss deepening their cooperation against nuclear smuggling and discouraging future North Korean missile tests, among other topics.

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1:10 p.m.

It's a tense start for Turkish President Recep Tayyip Erdogan's visit to Washington for a nuclear security summit.

Turkish security officials tried to remove a journalist at a policy institute where Erdogan is speaking.

Security guards at the Brookings Institution intervened, asking the Turkish officials to leave the room. Earlier, the officials had stopped the journalist - who works for opposition media - from entering.

Erdogan is facing increasing criticism for his crackdown on free speech. The journalist, identified as Adem Yavuz Arslan, has worked at outlets linked to U.S.-based Muslim cleric Fethullah Gulen - a bitter enemy of Erdogan.

Turkey's government has moved to seize control of some media outlets linked to Gulen.

Protesters gathered outside the Brookings event before Erdogan's arrival. A Turkish Embassy official declined comment.

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1:05 p.m.

A Chinese official says his country is dedicated to pursuing nuclear reprocessing - a step that some experts say poses a proliferation risk in East Asia.

But Xu Dazhe (shoo dah-juh) - chairman of the China Atomic Energy Authority - says China's negotiations with France to build a commercial plant that would separate plutonium from spent reactor fuel still have a long way to go.

Japan plans to open a long-delayed reprocessing plant in 2018, and South Korea has ambitions to reprocess, too.

Nonproliferation experts have called for a pause by all three nations to prevent mounting stockpiles of weapons-usable plutonium in a tense region.

Xu says reprocessing is needed for its development of nuclear energy, and China already has a pilot production line.

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12:50 p.m.

The White House says a strengthened nuclear safety agreement among nations is finally set to take force.

Nations in 2005 amended the Convention on the Physical Protection of Nuclear Material to expand its requirements. But it hasn't taken effect because it needed ratification from two-thirds of the countries.

The White House says 11 nations that recently ratified it have pushed the total past the two-thirds threshold. It's expected to take force in about a month.

The strengthened provisions cover nuclear material while it's being used, stored and transported. It also covers material being used for peaceful purposes, amid other provisions.

The announcement comes as world leaders converge for a nuclear security summit. The International Atomic Energy Agency has said the strengthened agreement will reduce the likelihood of terrorists getting their hands on nuclear materials.

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12:35 p.m.

President Barack Obama says the U.S., South Korea and Japan are working to make the Korean Peninsula nuclear-free.

Obama is meeting with Japanese Prime Minister Shinzo Abe (shin-zoh ah-bay) and South Korean President Park Geun-hye (goon-hay) as they attend a nuclear security summit in Washington.

North Korea's recent nuclear tests and rocket launch are causing concerns in the region and beyond.

Obama says the leaders discussed how to address the North Korean threat and nuclear proliferation. He says they also spoke about global challenges including climate change and cancer research.

Park says it's important to enforce a U.N. Security Council resolution regarding North Korea - and that the North is certain to face stiffer penalties if there are further provocations.

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12:10 p.m.

Georgia's president says Moscow's support for separatists is hampering efforts to prevent smuggling of nuclear and radiological materials along Russia's borders.

Giorgi Margvelashvili is in Washington for a nuclear security hosted by President Barack Obama.

The Georgian leader tells The Associated Press that it's difficult to know what's being smuggled through two breakaway territories of Georgia where Russian troops are stationed.

In recent years, Georgian investigators have arrested smugglers with nuclear or radioactive material - sometimes trafficked through the breakaway regions.

More than 50 countries and international organizations are attending the summit, but Russian leaders are skipping it, amid tensions with Washington.

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11:25 a.m.

A Chinese official says Beijing is committed to improving nuclear security, including the threat of cyberattacks on power plants.

Xu Dazhe (shoo dah-juh) leads the China Atomic Energy Authority. He's in Washington for a summit on preventing nuclear terrorism and countering nuclear smuggling.

Xu says China is working with the U.S. and other nuclear powers on control and safety measures. He says cyberattacks "present a very serious threat to our power industry, financial industry and nuclear facilities."

Chinese President Xi Jinping (shee jihn-peeng) is set to meet President Barack Obama later Thursday.

Nuclear safety is seen as an area of cooperation between the two world powers, but cybersecurity is a source of tension.

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10:25 a.m.

President Barack Obama says more must be done to rid the world of nuclear weapons.

He's calling on Russia to further reduce its nuclear weapons stockpile. He says the U.S. and its allies will continue standing up to North Korea over its continued nuclear tests and missile launches.

Obama says achieving a world without nuclear weapons won't happen quickly and perhaps not in his lifetime. But he says the work has begun.

He's making his views known in an opinion piece in The Washington Post as world leaders assemble in Washington a nuclear security summit.