Bahrain Mirror - AP: Supporters of an activist detained in Bahrain as part of an intensifying crackdown on dissent say he's been taken to the hospital with an irregular heartbeat.

Sayed Alwadaei, of the Bahrain Institute for Rights and Democracy, said Tuesday that activist Nabeel Rajab was at the cardiac care clinic of an unidentified hospital after being "in isolation for 15 days."

Bahraini officials did not immediately respond to a request for comment.

Rajab is the president of the Bahrain Center for Human Rights. He helped lead protests during Bahrain's 2011 demonstrations as the island's majority Shiite population and others demanded more political freedoms from its Sunni rulers.

Bahrain, home to the U.S. Navy's 5th Fleet, has launched a new crackdown on activists since April.