The United States on Friday promised further sanctions to pressure Venezuela's leftist leader Nicolas Maduro, accusing him of bribing lawmakers to block the re-election of his opponent Juan Guaido.

El Salvador has ordered Venezuela's diplomats to leave the country within 48 hours, in line with President Nayib Bukele's position that the Venezuelan government of Nicolas Maduro is illegitimate.

Venezuelan authorities late on Saturday confirmed the death of a military officer who opposition leaders and family members said was tortured in custody after his detention over alleged involvement in a coup plot against President Nicolas Maduro.

Venezuelan authorities have arrested six members of the country's military and police forces over the weekend, according to relatives of the detainees and human rights activists, as President Nicolas Maduro seeks to weed out dissent.

The Pentagon on Wednesday appeared to downplay any active planning to directly intervene in Venezuela to topple President Nicolas Maduro, telling Congress it had not been given orders to prepare for war and stressing support for diplomacy.

Venezuelan opposition leader Juan Guaido on Tuesday called for a military uprising to oust President Nicolas Maduro and violence broke out at anti-government protests as the country hit a new crisis point after years of political and economic chaos.

Russia's Ministry of Foreign Affairs on Tuesday accused the opposition in Venezuela of resorting to violence in what it said was a brazen attempt to draw the country's armed forces into clashes.

A new blackout across large parts of Venezuela, including the capital Caracas, forced many to spend another night in the dark on Tuesday, AFP and accounts published on social media said.

Venezuelan opposition leader Juan Guaido on Saturday launched what he promised will be a "definitive" escalation of pressure to force the country's embattled leftist leader from office.

Venezuela's opposition leader Juan Guaido urged his supporters to demonstrate in the streets Saturday to maintain pressure on his rival President Nicolas Maduro, amid rising anger over the collapse of public services.

The United States on Monday accused Russia of "reckless escalation" of the situation in Venezuela by deploying military planes and personnel to the crisis-stricken South American nation that Washington has hit with crippling sanctions.

Russian and US diplomats are to meet in Rome to discuss the crisis in Venezuela on Tuesday, according to the Foreign Ministry in Moscow.