Photos and videos of the man have flooded Venezuelan social media.
General Motors Venezolana said Thursday that it was forced to cease operations in Venezuela due to an illegal judicial seizure of its assets.
Hector Riera, 43, a product analyst who has worked with GM Venezuela for 16 years, was among many who appeared convinced the plant been confiscated by dealers connected with GM.
Humberto Valera, another GM employee, said no cars or other assets have been taken from the plant.
The State Department said Thursday it was reviewing details of the GM case but called on authorities to act swiftly and transparently to resolve the dispute. The statement said a fair judicial system is critical to economic reforms that would restore growth, but it made no mention of any action the USA government might take.
Hundreds of workers desperate for information about their jobs gathered at the plant on Thursday to meet with government and military officials, as well as representatives of the dealership that brought the lawsuit.
The Venezuelan government had no comment about the GM factory. Supporters of the president, who was elected in 2013 and assumed the socialist mantle of late leader Hugo Chavez, say the opposition's street protests are violent disruptions of public order that exceed the rights of free assembly and would not be tolerated in any other country. Venezuela is now fighting claims of illegal asset seizures at a World Bank-sponsored arbitration panel from more than 25 companies. Machado said the government was trying to blame her party for the killing of a young woman that the administration itself was responsible for.
But Venezuelan Foreign Minister Delcy Rodriguez mocked him in a tweet, saying: "The world and Venezuela are deeply concerned by the recent bombings launched by the U.S. on Syria and Afghanistan".
"We call on the Government of Venezuela and the opposition to engage sincerely to reactivate dialogue efforts", United Nations spokesman Stéphane Dujarric said in a press release. It was unclear how many people remained in custody.
At around midday on Thursday, a few thousand people protested in Caracas, although opposition lawmakers accused security forces of using excessive tear gas and force to block the marches. "There are those at the top, including Maduro himself, who appear genuinely to believe that this is a revolution and the ultimate goal is the replacement of the capitalist economy with one that is entirely state-run".
"Those responsible for the criminal repression of peaceful democratic activity. will be held individually accountable for their actions by the Venezuelan people and their institutions, as well as the worldwide community", the statement read.
The EU's executive commission said Thursday that it was "saddened" by the deaths of two young people during Wednesday's protests.
Eight people have died so far in demonstrations over the past several weeks.
The new marches come after a massive demonstration Wednesday left at least three dead - including a member of the security forces - and dozens arrested.
It added that the seizure was arbitrary and that it would vigorously take all legal action, within and outside of Venezuela, to defend its rights.
On Wednesday, opposition governor and two-time presidential candidate Henrique Capriles suggested that protests were the only long-term strategy, saying they should continue "until Nicolás Maduro understands that he must respect the constitution".
The company said the "illegal judicial seizure" would cause "irreparable damage" to GM, its suppliers, its 79 dealers and almost 2,700 employees of the plant.