(CNN) - Venezuelan authorities have detained the captain of a U.S.-flagged ship docked in a northwestern port city, according to crew members on board.
An official at the U.S. Embassy in Venezuela said the captain and 15 crew members on board the ship had been held in Maracaibo, Venezuela, and that U.S. authorities were trying to find out additional information from Venezuelan officials.
Earlier Thursday, a U.S. State Department official who asked to remain anonymous said the department was "looking into the status of the captain and crew of the U.S. vessel, Ocean Atlas, currently anchored in Maracaibo."
"We are in contact with the government of Venezuela on the matter, and are working to provide all appropriate consular assistance at the earliest opportunity," the official said.
Venezuelan officials did not immediately respond to requests for comment.
A crew member on the ship who asked to remain anonymous because of security concerns said the ship had been detained for nine days and the captain had been taken from the ship Wednesday night.
The crew member said arrest warrants had been issued for the entire crew.
"We have to go two at a time to the jail for questioning," he said in a Facebook post.
The sister of another crew member, who has been in regular contact with her brother and asked not to be identified for security reasons, said crew members held aboard the ship have heard that the captain has been charged with arms trafficking. The captain was detained after he refused to let authorities arrest the crew, she said.
