Venezuelan President Nicolas Maduro

President Nicolas Maduro called Monday for direct talks with his Guyanese counterpart to resolve mounting tensions between the two South American neighbors over a disputed border region rich in oil.

"There is only one solution here and that is to resume dialogue, face to face, directly," Maduro said during his weekly broadcast on public television.

In remarks directed to Guyanese President Irfaan Ali, Maduro said: "I am ready to meet with you very quickly, at the location of our choice in the Caribbean... to resume peace negotiations and put an end to these threats."

The two countries have been locked in a diplomatic duel since Guyana began auctioning off oil blocks in the Essequibo region, which Caracas claims as part of its territory.

Venezuela has long argued that the 160,000-square-kilometer (62,000-square-mile) region, administered by Guyana, should fall within its borders.

A former Dutch and British colony, Guyana says its border with Venezuela was fixed by an arbitration tribunal in 1899.

But Venezuela says the Essequibo river to the east of the region forms a natural frontier between the two countries that was recognized as the border in 1777.

The row intensified after US oil giant ExxonMobil discovered crude oil deposits off the region's coast in 2015.

On Saturday, Maduro accused Ali of "transforming Guyana into an ExxonMobil branch."

Guyana's actions, said Maduro, "violate international law and endanger peace in the region."

The CARICOM Caribbean bloc on Friday issued a statement expressing its "grave concern" over the spat.

"CARICOM views the stated intention of Venezuela to 'apply all the necessary measures' to prevent the operations licensed by Guyana in its waters, as a threat of the use of force contrary to international law," it said.

Last week, Venezuela's parliament proposed organizing a referendum on the region, prompting Guyana to summon the Venezuelan ambassador.