A US-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 US citizens, will be held on board while an investigation continues.
Admiral Angel Belisario Martinez told local station Union Radio on Sunday that the research ship was conducting "unauthorised 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 under a concession from Guyana.
Guyana's government says the crew was well within Guyana's territorial waters.
On Friday, Venezuela's foreign ministry said in a statement that the vessel was detected and intercepted because "it was carrying out illegal activities" within an ocean border area claimed by Caracas.
Guyana earlier said that a Venezuelan navy ship had confronted the Teknik Perdana on Thursday as it explored off the coast of Essequibo.
"Venezuela expresses its most energetic protest" because of the prospecting and exploratory activities on the "Venezuelan maritime ocean bed" carried out by the Teknik Perdana, Caracas said.
Venezuela and Guyana remain locked in territorial disputes concerning the Essequibo region, a wrangle that dates back to the 19th century.
The Guyana statement said the Teknik Perdana had been conducting a multi-beam survey of the seafloor when it was stopped.
"One point is clear and that is that the Teknik Perdana was in Guyana's waters when this incident took place," the foreign ministry statement said, demanding the immediate release of the ship and its crew.
"The government of Guyana is of the firm belief that the actions taken by the Venezuelan navy vessel constitute a serious threat to the peace of this sub-region and the government of Guyana therefore strongly condemns these actions," it added.