Guardian journalist Glenn Greenwald warns that he will publish many more documents about the British government’s surveillance activities, after his partner was detained and questioned at a London airport this weekend.

From Reuters (via Huffington Post):

“I will be far more aggressive in my reporting from now. I am going to publish many more documents. I am going to publish things on England too. I have many documents on England’s spy system. I think they will be sorry for what they did,” Greenwald, speaking in Portuguese, told reporters at Rio’s airport where he met Miranda upon his return to Brazil.

“They wanted to intimidate our journalism, to show that they have power and will not remain passive but will attack us more intensely if we continue publishing their secrets,” he said.

Greenwald’s partner David Miranda was questioned for nine hours this weekend under a controversial anti-terrorism law, and asked specifically about the Guardian journalist’s NSA reporting.

Miranda had been visiting in Berlin with Laura Poitras, the US filmmaker who produced the video interview that unmasked Edward Snowden to the world as the source of the NSA surveillance program leaks, and collaborated with Greenwald on the NSA reporting.  Authorities are said to have questioned Miranda about Poitras as well.  Several pieces of his electronic equipment were confiscated.

British authorities and the US both deny that the US directed any of the activities related to Miranda’s detention.

From NBCNews.com:

The White House on Monday directed questions about Miranda’s detainment to the British government, saying that the decision to question him was made without the involvement or direction of the United States.

The British government did provide a “heads up” to American authorities that it planned to question Miranda, but “the United States was not involved in that decision or that action,” said spokesman Josh Earnest.

“This was the British government, making a decision based on British law, on British soil about a British law enforcement action,” Earnest said.

Greenwald has previously warned that information yet to be released from Snowden’s stash of leaked files could prove to be the US’ “worst nightmare” if released.