JIM LEHRER: There were fresh developments today in several points around the world, all critical to U.S. policy-makers.
Margaret Warner reports.
MARGARET WARNER: President Obama put foreign affairs back in the foreground this week with a surprise Sunday trip to Afghanistan. He privately urged Afghan President Hamid Karzai to work harder on fighting corruption, something Karzai promised to do after his disputed reelection.
But, today, Karzai insisted the election fraud wasn't committed by his partisans. Instead, he blamed top officials of the U.N. and the European Union.
HAMID KARZAI, president of Afghanistan (through translator): This is the reality, brothers. For this reason today, I come here to talk to the members of the Independent Election Commission about fraud in the presidential election and provincial election. No doubt, there was huge fraud. There was vast fraud. The fraud is not by the Afghans. This fraud has been done by foreigners.
MARGARET WARNER: Karzai singled out American Peter Galbraith, a former U.N. official in Afghanistan. He was fired last year in a dispute with his boss over how to deal with fraud allegations.
In Washington, State Department Spokesman P.J. Crowley didn't comment directly on the Karzai accusation. Instead, he put the onus squarely back on the Afghan leader.
P.J. CROWLEY, U.S. assistant secretary of state for public affairs: Karzai has to step forward, lead his government, you know, in terms of convincing the international community and the Afghan people that they are taking measurable steps to reduce corruption.
MARGARET WARNER: Karzai's latest claim threatened to add to frictions with Washington, at a time when U.S. troops are building up for a major offensive against the Taliban in Kandahar. President Obama has been hoping for both military and political progress in Afghanistan, as he tries to wind down the conflict on another front, Iraq.
That effort in Iraq could be complicated by the lack of a clear outcome of last month's parliamentary elections. Prime Minister Nouri al-Maliki has claimed fraud, after losing narrowly to his main opponent, Ayad Allawi, a secular Shiite. Both sides are now angling to form a governing coalition.
Today, a leading Shiite religious party that placed third in the elections said it would not join any government without Allawi as prime minister. Separately, anti-American cleric Muqtada al-Sadr said yesterday his supporters will hold a referendum tomorrow and Saturday on their choice to be prime minister.
In the meantime, U.S. diplomatic tensions continued rising with Iraq's neighbor Iran over its nuclear program. Iran's top nuclear negotiator arrived in Beijing today, amid reports that China may drop its longstanding opposition to imposing more sanctions on Iran.
At a news conference, a Chinese foreign ministry spokesman would neither confirm nor deny the reports. Instead, he said his government wants Iran to cooperate with the U.N.'s nuclear watchdog, the International Atomic Energy Agency.
QIN GANG, spokesperson, Chinese foreign ministry (through translator): We oppose Iran having nuclear weapons. At the same time, we believe as a sovereignty, it has rights to use peaceful nuclear energy. But any country, even if they develop nuclear projects for peaceful purposes, they should accept the supervision of the IAEA, so as to ensure the program is for a peaceful purpose.
MARGARET WARNER: On Tuesday, President Obama and French President Sarkozy met in Washington and said they want the U.N. Security Council to act soon on new sanctions.
U.S. PRESIDENT BARACK OBAMA: My hope is that we are going to get this done this spring. So I'm not interested in waiting months for a sanctions regime to be in place. I'm interested in seeing that regime in place in weeks.
MARGARET WARNER: A change in China's position could clear the way for action by the Security Council.
China's relations with the U.S. had been strained of late over American arms sales to Taiwan and other issues. But Beijing announced today that Chinese President Hu Jintao will attend a nuclear security summit in Washington later this month.