The four were charged with participating in an illegal demonstration over the weekend, among other things, but they were ordered released from custody while the case is further investigated, the office of Bahrain's public prosecutor said Tuesday.
The Americans -- freelance journalist Anna Therese Day and three members of her TV crew -- were in Bahrain to cover the fifth anniversary of the start of mass pro-reform protests inspired by the Arab Spring
, the journalist advocacy group Reporters Without Borders said.
The group said the four were released without being subject to travel restrictions. After their release, they intended to depart Tuesday evening on a flight to the United Arab Emirates, said their lawyer in Bahrain, Mohammed al-Jishi.
"While we believe the four should not have been held at all, we are grateful to the Bahraini authorities for facilitating their timely release," the journalists' families said in a joint statement Tuesday. "We are awaiting news of their current location and hope they will be free to return to the United States as soon as possible."
Details of what the four are accused of doing have been sparse. Reporters Without Borders said they were accused of working as journalists without permission, with one arrested during a demonstration, charged with illegal behavior toward security forces.
Bahrain police said the four used false information to enter the country, and one was accused of concealing his or her face "with a cloth and participating in attacks on police alongside other rioters in Sitra" on Sunday.
The demonstration in Sitra was among those marking the fifth anniversary of Bahrain's 2011 anti-regime protests.
"Ever since the February 2011 protests, it has been difficult for foreign journalists to obtain work visas in the run-up to their anniversary," said Alexandra El Khazen, head of Reporters Without Borders' Middle East desk. "The authorities hope to control the situation by keeping unwanted witnesses of new protests to a minimum."
Bahrain is a small island nation with a predominantly Shiite population ruled by a Sunni minority. Sitra is a predominantly Shiite neighborhood south of the capital, Manama.
Bahrain police said they dispersed the rioters in accordance with Bahraini law.
All four Americans entered the country between Thursday and Friday, providing false information that they were tourists, the Bahrain Interior Ministry said.
Day's family said earlier this week that she "and her crew are committed journalists who only want to ensure they could undertake their profession ethically and thoroughly."
"The allegation that they were in any way involved in illegal behavior or anything other than journalistic activities is impossible," the family said in a prepared statement.
"Anna Day is much loved and missed and we are concerned about her well-being as well as that of her three American colleagues," the statement read.
Day, who has done freelance work for CNN in the past, has reported for various media outlets, including The New York Times, Al Jazeera English and CBS.
The U.S. Embassy in Bahrain said it was "aware of the arrest of four U.S. citizens in Bahrain" on Sunday but provided no further comment because of privacy concerns.
According to the New York-based Committee to Protect Journalists, at least six other journalists are in prison in Bahrain in connection with their work.
"It is sad that the fifth anniversary of the protests is marked by the arrest of yet more journalists in Bahrain, which has since become one of the worst jailers of journalists in the Arab world," said Sherif Mansour, the committee's Middle East and North Africa program coordinator. "We call for the immediate release of the four journalists arrested today and all other journalists who have been imprisoned over the past five years."