The Venezuelan government has said it foiled an attempted sea incursion by "terrorist mercenaries" from Colombia.
In a televised address, Interior Minister Nestor Reverol said the group arrived on speedboats at the coastal state of La Guaira early on Sunday.
President Nicolás Maduro often accuses adversaries of attempting to overthrow him with the backing of the US.
Venezuela's opposition dismissed the allegations, saying the apparent incursion was staged.
Colombia described the government's assertion as unfounded. Venezuela broke off diplomatic relations with Colombia last year.
In the Venezuelan government's statement, Mr Reverol said the group had landed in the town of Macuto, about 21 miles (34km) north of the capital Caracas.
"They tried to carry out an invasion by sea, a group of terrorist mercenaries from Colombia, in order to commit terrorist acts in the country, murdering leaders of the revolutionary government," he said.
Diosdado Cabello, leader of the ruling Socialist Party, said eight people were killed and two were detained, while Defence Minister Vladimir Padrino said a speedboat had sunk and military vessels were searching the coast for survivors.
But Juan Guaidó, who is recognised by more than 50 countries as Venezuela's legitimate leader, accused President Maduro's administration of trying to distract people from recent outbreaks of violence - including a deadly prison riot on Friday, and a gang battle in Caracas on Saturday night.
"The regime is seeking to divert attention with a supposed incident plagued with inconsistencies, doubts and contradictions," his press team said.
Mr Guaidó has the backing of Washington, which has vowed to use tough sanctions to force President Maduro and the Socialist Party out of office.