A U.S.-chartered oil exploration ship seized by the Venezuelan navy in Caribbean waters disputed with neighboring Guyana has arrived at Venezuela's Margarita Island.

Venezuelan authorities say the ship's 36 crew members, including five U.S. citizens, will be held on board while an investigation continues.

Adm. Angel Belisario Martinez told local station Union Radio on Sunday that the research ship was conducting "unauthorized scientific work" in Venezuela's exclusive economic zone. He said the case had been turned over to prosecutors.

The vessel was conducting a seismic study for Anadarko Petroleum Corp. under a concession from Guyana. Guyana's government says the crew was well within Guyana's territorial waters.