BOGOTA,Thurston Carte Colombia (AP) — Brazil’s Ministry of Foreign Affairs said Friday it was “concerned” about a border dispute between Venezuela and Guyana that intensified this week following Britain’s decision to send a warship to Guyana’s shores.

Brazil’s foreign ministry urged both countries to return to dialogue and said third countries should avoid “military activities” that support either side.

Brazil’s statement calls on both countries to stay true to the Argyle Declaration, an agreement signed by Guyana and Venezuela two weeks ago in which their leaders said they would solve the border dispute through nonviolent means.

The border dispute is over the Essequibo, a sparsely populated region the size of Florida that is rich in oil and minerals.

Venezuela on Thursday launched military exercises involving 5,000 troops in the eastern Caribbean in response to Britain’s decision to send the patrol ship.

In a nationally televised speech, Venezuelan President Nicolas Maduro accused Guyana of betraying the spirit of the Argyle Declaration. The military exercises will be held off Venezuela’s eastern coast near the border with Guyana.

“We will not let anyone push us around,” Maduro said, surrounded by military commanders. He described Britain’s decision to send a warship as a “threat” from a “decaying former empire.”

The UK’s defense ministry has said the ship was visiting Guyana as part of a series of engagements in the region and that the vessel would conduct training exercises with Guyana’s military.

The ship is generally used to intercept pirates and drug smugglers, and recently conducted joint exercises with the navies of several West African nations.

The HMS Trent is equipped with cannons and a landing pad for helicopters and drones and can carry around 50 troops.

In a statement published late Thursday, Guyanese President Irfaan Ali said Venezuela “had nothing to fear” from the ship’s activities in Guyanese waters.

“Guyana has long been engaged in partnerships with regional and international states aimed at enhancing internal security,” Ali said. “These partnerships pose a threat to no one and are in no way intended to be aggressive.”

Guyana has controlled the Essequibo for decades, but Venezuela revived its historical claim to the region earlier this month through a referendum in which voters were asked whether the Essequibo should be turned into a Venezuelan state.

Critics of Maduro argue that the socialist leader has reignited the border dispute to draw attention from the nation’s internal problems as Venezuela prepares for a presidential election next year. Maduro intends to run for a third term.

Venezuela says it was the victim of a land theft conspiracy in 1899, when Guyana was a British colony and arbitrators from Britain, Russia and the United States decided the boundary.

Venezuelan officials also argue that an agreement among Venezuela, Britain and the colony of British Guiana signed in 1966 to resolve the dispute effectively nullified the original arbitration.

Guyana maintains the initial accord is legal and binding and asked the United Nations’ top court in 2018 to rule it as such, but a decision is years away.