He said there were four protesters inside and that they still have enough food and water to continue the sit-in.
Despite U.S. sanctions, the upper echelons of Venezuela's military have largely ignored entreaties from the opposition and Washington to turn against Maduro and just over 1,000 troops have defected, mostly to Colombia and Brazil.
A crowd of Venezuelan expatriates who demand the eviction of the activists remained outside the building, along with a large police presence.
Ramon Rangel, who identified himself as an air force general, said the Venezuelan government is being controlled by the "communist dictatorship" in Cuba - a key Maduro ally.
He has previously accused the socialist leader of terrorism for his heavy-handed response to demonstrations.
"Selective extrajudicial executions, arbitrary detentions, and deaths and injuries caused by the excessive use of force by Nicolas Maduro's government as part of a systematic and widespread policy of repression since at least 2017 may constitute crimes against humanity", the rights group said in a statement based on a new report.
The United Nations plans to appoint a humanitarian coordinator soon to oversee a rollout of aid to Venezuela.
More than 50 countries have meanwhile recognized Guaido as Venezuela's legitimate leader.
During massive anti-government protests from 21 to 25 January this year, at least 47 people were shot dead in 12 of the country's 23 states, according to Amnesty.
Maduro himself "knew about these public and appalling acts and took no measures to either prevent or investigate them", it said.
From early Tuesday, the security services cordoned off the building housing the National Assembly.
Claver-Carone, who is one of the Trump administration's key national security advisers, said: 'One of the positive elements [of the uprising] is that there were many people involved. Bullet-proof vehicles and a tow truck were parked in the surrounding streets.
Guaido insisted the move would not stop lawmakers from doing their job.
"Whether it's in a square, in the annex buildings, under a bridge, the Assembly will sit and there will be a session", said congressman Luis Stefanelli.
"The government reaffirms its position of non-intervention, its openness to dialogue and its firm commitment to collaborate in finding a democratic, peaceful and collaborative solution to the situation that Venezuela faces", it said in a statement.
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