The United States on Saturday denounced what it said were Venezuelan naval vessels threatening an ExxonMobil unit in maritime territory claimed by Guyana.

The statement, which warned of consequences if there were further provocation from Caracas, came hours after Guyanese President Irfaan Ali said a Venezuelan patrol boat had "approached various assets in our exclusive waters" around 7 a.m. local time (1100 GMT).

Guyana had "put its international partners on alert," he said on Facebook.

The U.S. State Department warned against any further encroachment.

"Venezuelan naval vessels threatening ExxonMobil's floating production, storage and offloading (FPSO) unit is unacceptable and a clear violation of Guyana's internationally recognized maritime territory," said the statement from the department's U.S. Bureau of Western Hemisphere Affairs.

"Further provocation will result in consequences for the Maduro regime," it warned.

English-speaking Guyana, long one of the poorest countries in Latin America, has seen heightened tensions with Venezuela over control of the disputed Essequibo territory, a sprawling region rich in natural resources.

Tensions have flared since 2015, after petroleum giant ExxonMobil discovered enormous oil deposits that gave Guyana, a country of 800,000 people and with small military, the largest crude oil reserves in the world.

The government in Georgetown granted a new contract in April 2024 to ExxonMobil, further fueling tensions.

Ali said on Facebook that the floating production vessels were "operating legally within Guyana's exclusive economic zone."

"Guyana remains committed to peace and the rule of law," he said in a later post.

"We will continue to seek diplomatic solutions, but we will not tolerate threats to our territorial integrity," he said.

Venezuela, for its part, said it "categorically repudiates the unfounded statements" by Ali, claiming he was "blatantly lying" by saying its navy had violated Guyana's territory.

"Those waters are not part of Guyanese territory, since it is a maritime zone pending delimitation in accordance with international law," a foreign ministry statement said.

Tensions were fanned on Feb. 17 when Guyana said six of its soldiers were wounded when a supply transport was ambushed, allegedly by members of a Venezuelan criminal gang.

That happened on the anniversary of the signing of a 1966 agreement between Venezuela and Britain, reached before Guyanese independence, which called for a negotiated solution to the territorial dispute.

Guyana, however, insists that an earlier 1899 ruling has fixed the disputed border in its favor.

In 2023, Venezuela's socialist President Nicolas Maduro proposed declaring a Venezuelan province in the disputed territory.

Ali and Maduro met amid the heightened tensions in December that year for talks on neutral ground, in Saint Vincent and the Grenadines.

They agreed to avoid any use of force, "directly or indirectly."

Weeks after the meeting, Britain sent the patrol ship HMS Trent on a port visit to Georgetown, a gesture Maduro deemed a "provocation and threat by the United Kingdom."

Venezuela then launched a major military exercise in the border region, including more than 5,600 soldiers, F-14 fighter jets, amphibious vessels and patrol boats.