David Miranda, Glenn Greenwald’s partner, detained at London airport

The partner of Guardian journalist Glenn Greenwald was detained at London Heathrow airport for nine hours Sunday under the UK's counterterrorism laws, a move that Greenwald deemed "despotic." 

Greenwald's partner, David Miranda, was passing through Heathrow on his way from Berlin to Rio de Janiero when he was stopped by authorities. 

According to the New York Times, the Brazilian national had been paying a visit to Laura Poitras, a documentary film-maker who has been working with Greenwald to disseminate Edward Snowden's controversial National Security Agency leaks. 

London's Metropolitan Police confirmed they had detained a 28-year-old man, citing "Schedule 7 of the Terrorism Act 2000" for their action, according to AFP. He was not arrested.

Schedule 7, controversial in the UK, allows authorities to stop and question people passing through border crossings for up to nine hours — though according to the Guardian, most such stops last for less than one hour. 

Miranda said that officers didn't attempt to question him about possible terrorism, his partner claimed. "They spent the entire day asking about the reporting I was doing and other Guardian journalists were doing on the NSA stories," Greenwald told the BBC World Service's "Newsday" program.

Miranda's supporters claim his laptop, a memory stick, and other electronics were confiscated from him.

"This is a profound attack on press freedoms and the news gathering process," said Greenwald in a Guardian statement.

"To detain my partner for a full nine hours while denying him a lawyer, and then seize large amounts of his possessions, is clearly intended to send a message of intimidation to those of us who have been reporting on the NSA and GCHQ [Government Communications Headquarters, the British equivalent of the NSA]. 

"The actions of the UK pose a serious threat to journalists everywhere."

"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.

The government of Brazil has formally objected to Miranda's detention, expressing "grave concern" about their citizen being "held incommunicado" at Heathrow, said AFP.

The US government said British officials gave it a "heads up" when Miranda was detained, but said it was not involved in the decision. The US said the decision was made "independent of our direction," according to BBC news.

Amnesty International also protested the incident. "David's detention was unlawful and inexcusable," wrote Widney Brown, Senior Director of International Law and Policy at Amnesty International, in a statement on the organization website.

"He was detained under a law that violates any principle of fairness and his detention shows how the law can be abused for petty vindictive reasons," said Brown.