Authorities in the United Arab Emirates have detained two journalists working for Swiss broadcaster RTS while they were covering the opening of the new Louvre museum in Abu Dhabi, and held them for two days.

Journalist Serge Enderlin and cameraman Jon Bjorgvinsson were held on Thursday when they were taking pictures at an open-air market in Abu Dhabi, according to the channel.

They were accredited to cover the museum's opening and interview French architect Jean Nouvel, who designed the Louvre Abu Dhabi.

UAE security forces detained the duo for more than 50 hours, without allowing them contact with the outside world, the channel said, adding that they were subjected to interrogations that sometimes lasted 10 hours straight.

They were blindfolded while being transported to different facilities, and their camera, computers, storage disks and other equipment were confiscated, RTS said.

"We were separated, our phones and watches confiscated, and were put in total isolation," said Bjorgvinsson in an interview with RTS. "They never hurt us, but their interrogations were tough and took a very long time," he added.

Abu Dhabi authorities wanted to know why they had taken pictures of the market and seemed irritated by the Swiss' portrayal of migrant workers, according to the channel. They also questioned them about their collaboration with NGO's and third states.

"The electronic data on my phone has been violated," Enderlin said. The security forces made him give up the codes to his phone in the face of what he called "blackmail" after 25 hours of detention.

They finally had to sign a confession to be released, the channel said.

Speaking to Al Jazeera from Lausanne, Enderlin said he was not able to read the document, as it was in Arabic.

"We presumed that what we signed for was just a summary of what we've been saying during our interrogation. The officers were particularly interested in previous reporting trips I've made to Qatar in 2002 and 2003," he said.

"All we wanted to do was put the opening of the Louvre in a wider context - as a flip-side to the glitz of the museum we wanted to show the migrant workers who actually built it," Enderlin added.

"What was especially bothersome was the lengths of the procedures and the extreme intimidation."

The journalists were released on Saturday night and allowed to return to Zurich, leaving their equipment and much of their belongings behind, RTS reported.

"RTS condemns the press freedom violations against the journalists," Pascal Cretan, director of the channel, said in a press release.