The dismantling of the camps was announced just hours before top opposition leader Leopoldo Lopez, who's been in custody since February, was scheduled to appear in court. The hearing on whether he should begin trial on charges of inciting violence at anti-government protests was suspended and Lopez was returned to the military prison outside Caracas almost as soon as he arrived to the courthouse downtown.
The latest clashes also came as the U.S. Congress began debate Thursday on imposing economic sanctions against Venezuela's leaders.
State Department officials were to brief a Senate committee Thursday on the violent street protests that have rocked the country for weeks, and a House panel will finalize its version of a sanctions bill Friday.
The legislation in both chambers is relatively modest. It centers on banning visas for Venezuelan officials who crushed anti-government protests and freezes their assets.
The South American country has been roiled since February by demonstrations that have killed 41 people on all sides, and left another 785 injured. At least 2,200 people have been arrested in connection with the protests over the last few months.
Maduro's administration has grown increasingly fed up with the demonstrations and last week announced that it had arrested 58 foreigners, including an American, on suspicion of inciting violent street protests against the government.
Opponents have repeatedly rejected Maduro's frequent allegations that the protests are seeking his overthrow, calling them an effort to distract attention from economic problems such as 57 percent inflation and record shortages.
The opposition mayor for Caracas' Chacao municipality, Ramon Muchacho, said on his Twitter account that some 700 National Guard members and 200 police agents broke up the two camps in his jurisdiction somewhere between 3 and 3:30 a.m.
Hours later, the destroyed remnants of barricades built by the students could still be seen outside on camp city in front of the UN offices. A number of national guardsmen stood in front of the building as pedestrians walked by, some of them lobbing insults.
In Washington, U.S. Sen. Marco Rubio, R-Fla., a sponsor of the sanctions legislation in the Senate, said the message that penalties would carry is important. The move comes as human rights groups accuse Venezuelan security officials of arresting, torturing and even killing unarmed demonstrators.
"This is happening in our very own hemisphere," Rubio said in a telephone interview with The Associated Press. He said sanctions should target anyone responsible for human rights violations, refusing to rule out Maduro as a potential target.
Action now would show the U.S. is "firmly on the side of the democratic aspirations of the Venezuelan people," Rubio said.