奥巴马：伊朗必须承担责任

President Barack Obama says Iran's government must be held accountable for what he calls "dangerous and reckless behavior" in what the U.S. has alleged was a plot to assassinate Saudi Arabia's ambassador to the United States.  President Obama spoke during a joint news conference with South Korean President Lee Myung-bak.

Though their talks were wide-ranging, including the U.S.- South Korea free-trade agreement and tensions with North Korea, Mr. Obama was pressed about the U.S. response to the alleged plot.

Saying the facts are there for all to see, he said the United States knows Manssor Arbabsiar, a naturalized U.S. citizen with an Iranian passport charged in the case, had direct links and was paid and directed by individuals in Iran's government.

Mr. Obama called it a "dangerous escalation" and part of a pattern of dangerous and reckless behavior, adding Iran must pay a price in terms of further isolation.

"For Iran to have been involved in a plot like this indicates the degree to which it has been outside of the accepted norms of international behavior far too long," he said. "This is just one example of series of steps they have taken to create violence and to behave in a way that we don't see other countries doing."

Mr. Obama had this response when asked specifically if the United States knew whether Iran's top leaders had knowledge of the plot.

"Even if, at the highest levels, there was not detailed operational knowledge, there has to be accountability with respect to anybody in the Iranian government engaging in this kind of activity," he said.

At the State Department, spokeswoman Victoria Nuland said U.S. and Iranian diplomats had a meeting this past Wednesday, which an official said occurred at the United Nations, in which the alleged plot was discussed.  She provided no details.

A U.S. official said the United States is sending out special teams to brief foreign governments on the case, saying among those requesting briefings were China, Russia and Turkey.

On other subjects, President Obama and President Lee reaffirmed the strength of the U.S.-South Korea alliance, saying they remain completely united on their approach toward North Korea.  

"Our principled approach will remain steadfast," President Lee said. "We agreed that North Korea's continued pursuit of nuclear weapons poses a serious threat to peace and stability of the Korean peninsula and the world.  We will continue to work toward denuclearization of the peninsula."

"The choice is clear for North Korea," said President Obama. "If Pyongyang continues to ignore its international obligations, it will invite even more pressure and isolation. If the North abandons its quest for nuclear weapons and moves toward denuclearization, it will enjoy greater security and opportunity for its people."

Ratification by the U.S. Congress of the U.S.-South Korea free-trade agreement was a key focus of the Obama-Lee talks.  Both said the deal, which still must be approved by South Korea's national assembly, will help create jobs and expand exports.

President Lee conveyed his gratitude directly to U.S. lawmakers as he also addressed a joint meeting of Congress, before a state dinner at the White House.

Other topics in Thursday's discussions included Afghanistan, support for democratic transitions in the Middle East and North Africa, the global economy and the G20 and APEC summits in November, and South Korea's planning for the next Nuclear Security Summit in March.