"Terrorists" attacked a military base in Venezuela's third-biggest city of Valencia today, but soldiers defended it and arrested several people, officials said.
"In the early morning hours, terrorist attackers entered the Paramacay Fort in Valencia...," Diosdado Cabello, a Socialist Party leader, said on his Twitter account.
The situation was under control with "various terrorists detained," he added.
Local media and social networks spoke of a possible military uprising at the base against the government of President Nicolas Maduro, but there was no immediate confirmation.
One video was posted in which a man presenting himself as an army captain declared a "legitimate rebellion." Around him stood 15 other men dressed in camouflage, some of them armed.
He demanded the "immediate formation of a transitional government and free elections."
The head of the armed forces, Defense Minister Vladimir Padrino, tweeted: "They couldn't do anything against the FANB (military)... They try to assault it with terrorist attacks. They can't."
The reported unrest occurred as a new assembly with supreme powers and loyal to Maduro starting sitting in Venezuela, a week after it was elected in polls marred by violence and allegations that the results were tampered with.
The opposition and dozens of countries say the new body is illegitimate and serves only to create a "dictatorship" by bypassing the opposition-controlled legislature.
In its first act on Saturday, the body, the Constituent Assembly, ordered the dismissal of the country's attorney general, Luisa Ortega, who became a vociferous critic after breaking ranks with Maduro.