Venezuela and Guyana have been locked in a land dispute over the oil-rich Essequibo region which makes up about two-thirds of Guyana's territory, but has long been claimed by Caracas.

Venezuela's President Nicolas Maduro on Thursday ordered over 5,600 troops to join a "defensive" exercise near the Guyana border, in response to Britain sending a warship to the area in a show of support to its former colony.

Britain said Friday the Venezuelan military exercises were "unjustified and should cease."

London diverted the patrol vessel HMS Trent to Guyana "as part of a series of engagements in the region during her Atlantic patrol task deployment."

A Guyana foreign ministry source, speaking on condition of anonymity, confirmed the "uneventful" arrival of the warship in its waters on Friday.

Brazil, which borders both countries and whose President Luiz Inacio Lula da Silva has emerged as a peace broker of sorts, on Friday called for "restraint and a return to dialogue."

Expressing "concern," the Brazilian government said in a statement it "believes military demonstrations of support to either party should be avoided."

- 'Recklessness' -

Rocio San Miguel, a Venezuelan military expert and normally a critic of the government, said Britain's military response was "recklessness that forces Venezuela to respond as it has done."

However Gary Best, a former chief of staff of the Guyanan Defence Forces, said having the British ship in their waters was not "a provocation."

"It is nothing unusual. However, in the actual context... of the challenge to the sovereignty by Venezuela, it has taken on a new meaning.

"I can see how they would see it as a threat."

He said the military exercises were "a show of force" from Maduro, ahead of elections in 2024.

Venezuela's century-old claim on Essequibo has been revived since massive offshore oil deposits were discovered in the region and Guyana began handing out licenses to oil companies to operate there.

Maduro's government held a controversial referendum on December 3 in which 95 percent of voters, according to officials, supported declaring Venezuela the rightful owner of Essequibo.

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

Guyana, a former British and Dutch colony, insists the Essequibo frontiers were determined by an arbitration panel in 1899.

But Venezuela claims the Essequibo River to the region's east forms a natural border recognized as far back as 1777.

Brazil urged both parties to respect an agreement reached after Maduro and Guyana President Irfaan Ali met earlier this month in the Caribbean, where they vowed not to resort to force to settle the dispute.

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