According to a joint statement, the incident occurred at around 2:30 pm (1830 GMT) on Sunday on the Cuyuni River in the contested and oil-rich Essequibo region, which has been at the center of a territorial dispute between Venezuela and Guyana.

The patrol boat, which included military and police personnel, was escorting Guyana election officials distributing ballots to remote polling stations when it came under fire from the Venezuelan shore, the statement said.

"The patrol immediately returned fire and successfully manoeuvred the escort team out of danger. No injuries were sustained by any personnel, and no election materials were damaged or compromised," the statement said.

"Despite the incident, the team safely continued its journey and all remaining ballot boxes were successfully delivered to their assigned polling stations," it added.

On Monday, Guyana is holding elections for a new president and parliament for the country of 850,000 people, which has the largest per capita oil reserves on the planet.

Most of these reserves are located in Essequibo.

Guyana and Venezuela have each complained of gunfire targeting their boats in the past, but both typically refrain from blaming the other's armed forces.

Incumbent Guyana President Irfaan Ali has taken a firm stance against Venezuela and enjoys US support in his country's claims over the Essequibo territory.

Venezuela has been increasingly assertive and this year elected a governor to the region, despite Caracas having no authority there.