U.S. had advance notice of Britain’s plan to detain reporter Glenn Greenwal

Journalist Glenn Greenwald, left, walks with his partner, David Miranda, in Rio de Janeiro's International Airport. U.K. authorities detained Miranda Sunday as he passed through London's Heathrow Airport. Greenwald has close links to Edward Snowden, the former U.S. spy agency contractor who has been granted asylum by Russia.

U.S. officials on Monday distanced themselves from the decision of British authorities to detain the Brazilian partner of Glenn Greenwald, the journalist who has exposed details of National Security Agency surveillance programs, amid questions over the documents officials may have confiscated.

White House spokesman Josh Earnest told reporters that U.S. officials had received a “heads-up” that London police would detain David Miranda on Sunday, but he said the U.S. government did not request Miranda’s detention, calling it “a law enforcement action” taken by the British government.

“This was a decision that was made by the British government without the involvement and not at the request of the United States government. It’s as simple as that,” Earnest said.

Miranda, 28, was detained by British authorities at Heathrow Airport on his way back home to Rio de Janeiro, having spent the previous week in Berlin with Laura Poitras, a documentary filmmaker who has been working with Greenwald and former NSA contractor Edward Snowden, who leaked NSA data to Greenwald and others.

Authorities interrogated Mi­ran­da for nine hours — the maximum allowed under the law that permitted his detention — and confiscated several items from him, including his laptop computer, cellphone, DVDs, USB sticks and video-game consoles.

Greenwald, in an e-mail on Monday, said his partner had been questioned about a variety of subjects including “what stories we were working on at that moment.”

“David was asked mostly about the work Laura Poitras, the Guardian and I were doing on NSA stories, as well as extensive information about me and Laura,” Greenwald said. “He was also asked about Brazil, the political situation in Brazil, and his friends and family.”

The Guardian said it paid for Miranda’s flights, and the paper’s editor, Alan Rusbridger, noted Monday that although Miranda is not a journalist, “he still plays a valuable role in helping his partner do his journalistic work.”

Greenwald declined to respond to a question about whether Miranda had served as a courier for classified material related to the paper’s NSA coverage. In an earlier exchange, however, he said he expected the data would be shared with U.S. authorities but was unconcerned.

“Everything he had — for his personal use and everything else — was heavily encrypted,” Greenwald said.

Earnest declined to say whether British authorities shared with the United States any intelligence they might have extracted from Miranda, as did a spokeswoman for the State Department.

Miranda was detained under Schedule 7 of Britain’s Terrorism Act 2000, which allows authorities to question individuals traveling through airports and border areas. In a 2012 review of the act, Britain’s Home Office said that more than 97 percent of people stopped under the law are questioned for less than one hour.

Several British politicians have demanded clarification on why antiterrorism laws were used to detain Miranda. Keith Vaz, chairman of Parliament’s Home Affairs Select Committee, wrote to police officials Monday asking them who authorized the decision, among other things.

“It’s an extraordinary twist to a complicated story,” Vaz told the BBC on Monday morning. “They may have a perfectly reasonable explanation,” he said of the authorities who detained Miranda, “ but if this is what is going to happen, if we are going to use the act in this way, for those issues that are not related to terrorism, then at least we need to know so everyone is prepared.”

The Guardian disclosed Monday that British authorities have attempted to pressure the paper to turn over the material leaked by Snowden, or to destroy it. Rusbridger, in a column, said that at some point over the past month, security experts from the GCHQ intelligence agency oversaw the destruction of two hard drives in the Guardian’s basement, even though he pointed out to officials that the paper’s NSA stories were being reported and edited out of New York.

“We will continue to do patient, painstaking reporting on the Snowden documents, we just won’t do it in London,” Rus­bridger wrote.