On Monday, President Nicolás Maduro signaled that he would crack down on his opponents, declaring that some of them “would end up in jail.”
A statement issued by the Supreme Court on Tuesday said that officials had received “information that revealed an escape plan” by Mr. Ledezma and Mr. López. It also said the two had violated the terms of their house arrest by making political statements.
The developments came just hours after the United States issued sanctions on Mr. Maduro, freezing any United States assets he owns, among other measures, for rights abuses and undermining democracy. Washington called on the Venezuelan president to release political prisoners from the opposition, and the Treasury secretary, Steven Mnuchin, called him a “dictator who disregards the will of the Venezuelan people.”
The seizing of the two men represents an about-face for the government, particularly in the case of Mr. López, who was released from military prison and placed under house arrest after a surprise decision on July 8. Some speculated that the early-morning developments would reinvigorate the opposition’s push against Mr. Maduro.
In late July, Mr. López released a short video from his home, urging the government to release political prisoners and accept humanitarian aid, and he called on his followers to join demonstrations and a national strike against the vote on the constituent assembly. However, he steered clear of more aggressive calls to action that he had been known for in the past.
A lawyer for Mr. López, Jared Genser, confirmed his arrest but did not comment further.
Early Tuesday, Mr. Ledezma’s daughter Oriette Ledezma posted a video on Twitter in which she criticized the government for her father’s arrest.
“He was kidnapped once again, they took him from his house in the middle of the night,” she said. “We don’t know his location. A group of people came with their faces covered, in camouflage and they took him away.”