(Adds Maduro, details of congress fracas)
By Diego Oré and Silene Ramírez
CARACAS, July 5 (Reuters) - The Venezuelan police officer who staged a helicopter attack on government buildings in Caracas last week appeared in an internet video on Wednesday vowing to continue fighting for the "liberation" of his country.
And in another chaotic day for Venezuela, convulsed by protests since April, pro-government groups burst into the opposition-controlled National Assembly, witnesses said, beating up several lawmakers and journalists.
Opponents of President Nicolas Maduro are demanding general elections to end socialist rule and solutions to the OPEC nation's brutal economic crisis. The government says the opposition is seeking a violent coup with U.S. support.
"Once again we are in Caracas, ready and willing to continue our struggle for the liberation of our country," police pilot Oscar Perez said in a video, wearing a military uniform and wool cap, with a Venezuelan flag and a rifle behind him.
He had not been seen since he hijacked a helicopter last week and flew through Caracas pulling a "Freedom" banner. He opened fire and dropped grenades on the Interior Ministry and Supreme Court, but nobody was injured.
Maduro, the 54-year-old successor to Hugo Chavez, called that attack a terrorist assault to overthrow him.
But many government critics doubt the official version, and some even suggested it may have been staged to divert attention from the country's economic and political crises.
In the video, Perez said the attack was "perfectly achieved" with no collateral damage "because it was planned, because we are not murderers like you, Mr. Nicolas Maduro."
Perez said he had staged an emergency landing on the Caribbean coast following the attack, and returned to the capital after hiking through mountains. The Information Ministry did not immediately respond to a request for comment.
Perez, who has portrayed himself as a James Bond-cum-Rambo figure on social media, is also an actor who starred in a 2015 movie about the rescue of a kidnapped businessman.
Though he has claimed wider support within the security forces, Perez's actions so far appear to be a rogue stunt organized by a small group of disaffected policemen.
Venezuela's opposition has been staging demonstrations against Maduro for three months, saying he has created a dictatorship and destroyed the country's economy.
At least 90 people have been killed in the protests.
They say Maduro is seeking to consolidate control through a Constituent Assembly, a superbody that will be elected at the end of July. The opposition has promised to boycott the vote, which it says is rigged in favor of the ruling Socialist Party.
"We are fully sure of what we are doing and if we must give up our lives, we will hand them over to the people," Perez said in the video. "If this constituent assembly takes place, there will be no Venezuela."
While Maduro was leading a military parade for Independence Day on Wednesday, the opposition-led National Assembly held a session. They denounced the president as a "dictator" and approved a plebiscite that the opposition is organizing for July 16, asking Venezuelans what they think of Maduro's plans.
During the session, pro-government groups gathered outside the legislature in downtown Caracas, and several dozen people burst into the compound armed with metal pipes, sticks and stones, attacking lawmakers and journalists, witnesses said.
At least three opposition lawmakers were beaten and several journalists were robbed, witnesses said. Two lawmakers staggered around the corridors with bloodied faces.
Explosions were heard around the building, probably from fireworks, witnesses said. One lawmaker, Americo De Grazia, was wheeled out on a stretcher to be taken away by an ambulance.
"This is Venezuela today," said the assembly vice president, Freddy Guevara. "Criminals attack the National Assembly, the armed forces are complicit in this madness, but the people and the lawmakers resist and advance."
In his Independence Day speech, Maduro condemned the violence in the assembly and asked for an investigation, but he also challenged the opposition to speak out about violence from within its ranks.
Young opposition protesters have frequently attacked security forces with stones, homemade mortars and Molotov cocktails, burned property. Protesters killed a man by dousing him in gasoline and setting him on fire.
"I want peace for Venezuela, I don't accept violence from anyone," Maduro said.
Additional reporting by Andrew Cawthorne; Writing by Andrew Cawthorne and Brian Ellsworth; Editing by Jeffrey Benkoe