DUBAI, United Arab Emirates (AP) — Bahrain has arrested four American journalists covering the anniversary of its 2011 uprising amid a long crackdown on dissent in the tiny island nation, witnesses said Monday.

Bahraini police said it detained four Americans for providing "false information that they were tourists," while also alleging one took part in an attack on its officers. The U.S. Embassy in Manama said in a statement Monday it was "aware of the arrest of four U.S. citizens in Bahrain" on Sunday but that it could not discuss the case due to privacy concerns.

The identities of the journalists and whether they worked for a specific media outlet was not immediately clear. Bahraini police said one was a woman and three were men.

Photographs of the reporters working in Sitra, a largely Shiite community south of the capital that has seen repeated protests, circulated on social media, including one image of a woman being filmed while speaking to a masked protester.

On Sunday, police arrested a photographer working with the group, the two witnesses said. Later that night, police surrounded the area with checkpoints and arrested the other three, the witnesses said. The witnesses spoke to The Associated Press on condition of anonymity for fear of being arrested.

An Interior Ministry statement alleged one of the four journalists "was wearing a mask and participating in attacks on police alongside other rioters in Sitra." The statement also said the journalists entered the country between Thursday and Friday on tourist visas.

"At least some of the arrestees were in the country as members of the international media but had not registered with the concerned authority and were involved in illegal activities," the statement said, without elaborating on what those activities were.

Bahrain requires international journalists to obtain special media visas before entering Bahrain to work. The island kingdom allows citizens of many countries, including the U.S., to get a tourist visa on arrival. Obtaining a media visa takes several days if granted, and activists say Bahrain has denied media visas for some journalists since the 2011 protests.

A statement on the state-run Bahrain News Agency said the journalists had "been afforded full legal rights in line with the kingdom's procedures and constitution while investigations continue."

Bahraini officials did not respond to questions from the AP about the arrests.

The 2011 protests in Bahrain, which is home to the U.S. Navy's 5th Fleet, were the largest of the Arab Spring wave of demonstrations to rock the Gulf Arab states. They were driven by the country's Shiite majority, who demanded greater political rights from the Sunni-led monarchy.

But while changes swept across the region, Bahrain's own protests found themselves put down after Saudi Arabia and the United Arab Emirates sent in reinforcements. Bahrain blamed regional Shiite power Iran for stirring up the demonstrations, though a government-sponsored investigation into the unrest said there wasn't "a discernable link" between the protests and the Islamic Republic based on the information the government gave them.

Bahrain's government committed to a number of reforms in the wake of the 2011 demonstrations, but low-level unrest continues, particularly in Shiite communities. Small groups of activists frequently clash with riot police and bombs occasionally target security forces. Hundreds of Bahraini youths protested Sunday on the fifth anniversary of the uprising.

Associated Press writer Adam Schreck contributed to this report.

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