David Miranda, partner of the Guardian correspondent Glenn Greenwald, was held for nine hours on Sunday at the Heathrow airport in the UK.
Greenwald was among the first reporters to publicise information leaked by whistleblower Edward Snowden about controversial phone and internet surveillance conducted by the US National Security Agency.
"There was a heads-up that was provided by the British government. This is something that we had an indication was likely to occur, but it is not something that we requested...
Greenwald, however has alleged that the detention at the airport was an act of victimisation.
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"This is an independent British law enforcement decision that was made. I know the suggestion has been raised by some that this is an effort to intimidate journalists.
"This is the British government making a decision based on British law, on British soil, about a British law enforcement action," Earnest said.
"They gave us a heads-up, and this is something that they did not do at our direction and it's not something that we were involved with. This is a decision that they made on their own," he added.
"But that detention was a decision that was made by the British government and is something that if you have questions about you should ask them," he said.
However, neither the White House nor the State Department rule out that the US had obtained information from Miranda's laptop.
"I'm just not in a position to talk to you about the conversations between British law enforcement officials and American law enforcement officials," Earnest said.