Venezuela’s President Nicolas Maduro on Thursday ordered more than 5,600 military personnel to participate in a defensive exercise, in response to Britain sending a warship to waters off Guyana.

Britain said Sunday it would divert the patrol vessel to Guyana, amid the simmering territorial dispute over the oil-rich Essequibo region.

A Guyana foreign ministry source said the ship was due to arrive Friday and would be in its territory for less than a week for open sea defense exercises.

A television broadcast accompanying Maduro’s announcement showed fighter jets, ships and ocean patrol vessels participating in the Venezuelan exercise.

The Venezuelan government earlier asked Guyana to withdraw the vessel, and to refrain from involving military powers.

President Maduro claims that Essequibo is Venezuelan land – a decades-old contention that has flared since massive oil deposits were found in its waters.

He has since started legal manoeuvres to create a Venezuelan province in Essequibo and ordered the state oil company to issue licenses for extracting crude in the region.