The White House Saturday welcomed Afghanistan's presidential elections as a "significant step" for the country's democracy, but emphasized the need for electoral commissions to legitimize the vote.

"The work of the electoral commissions in the weeks ahead will be particularly important," the White House said in a statement, commending "the voters, electoral bodies, and security forces for their commitment to the democratic process."

The White House said Wednesday it had adopted new procedures on President Barack Obama's foreign trips to avoid a repeat of the "inadvertent" release of the name of the CIA's station chief in Kabul last month. 

The station chief was named, contrary to intelligence community practices, in a pool report distributed to thousands of reporters based on information provided by White House officials. 

Some 600 children who crossed into the United States illegally and on their own from Mexico will be housed temporarily at a military base in Oklahoma, the Defense Department said Monday.

The children will probably start arriving at Ft. Sill this week, said a Pentagon spokesman, Col. Steven Warren.

President Barack Obama's decision to swap five detained Taliban operatives for an American soldier captured in Afghanistan has baffled lawmakers, with many questioning the military and political merits of the controversial exchange.

Some warned that the president, already burdened by a series of crises, has sunk deeper into political quicksand by negotiating with terrorists, keeping Congress in the dark or manufacturing a military success story in order to mask other scandals.

Fugitive self-proclaimed spy Edward Snowden admitted Wednesday he wants to return home, as he defended his massive leak of intelligence secrets, saying the abuse of the U.S. Constitution left him no choice.

"If I could go any place in the world, that place would be home," Snowden said almost a year to the day since he revealed a stunning US surveillance dragnet mining data from phones and Internet companies around the world, including Europe.

The White House has ordered an investigation into the blunder which saw the CIA's Afghanistan station chief accidentally identified, an official said Tuesday.

National Security Council spokeswoman Caitlin Hayden said White House Counsel Neil Eggleston has been asked to examine the circumstances surrounding the gaffe over the weekend.

President Barack Obama has postponed a review of U.S. deportation policy for undocumented workers, hoping to give legislative reform a better chance, a White House official said Tuesday.

U.S. President Barack Obama hailed "courageous" Ukrainians who went to the polls Sunday in a presidential vote that Washington and the West hope will bring stability back to the country after months of turmoil.

"Despite provocations and violence, millions of Ukrainians went to the polls throughout the country," the White House quoted Obama as saying.

U.S. Secret Service personnel sprang into action Friday outside the White House when a man stripped naked in what appeared to be a bizarre form of protest.

On one of the hottest days of the year so far in the U.S. capital, where temperatures hit at least 26 degrees Celsius (78 Fahrenheit), the man ambled up to Secret Service officers at the gate of the White House and then took off all his clothes.

The U.S.-led military presence in Afghanistan will remain "significant" despite this year's drawdown, Washington's special envoy for the country said Tuesday, as he predicted that outgoing president Hamid Karzai would continue to wield influence.

James Dobbins, the U.S. special representative for Pakistan and Afghanistan, told reporters in Tokyo that Washington was "still considering" the details of the withdrawal plan.