Orelis Lehmann gets ready to make coffee in her darkened apartment in Caracas, Venezuela, July 23, 2019.
Orelis Lehmann gets set to make coffee in her darkened apartment in Caracas, Venezuela, July 23, 2019. In neighborhoods like hers, darkness from a power outage lingered even as other parts of Caracas began springing back to life.

CARACAS, Venezuela — Venezuelan President Nicolas Maduro on Wednesday blamed the United States for a second widespread blackout this year that cast most of the South American nation in darkness amid an opposition campaign to overthrow him.

Cuban officials, meanwhile, underscored that their support for Maduro is unwavering, saying U.S. attempts have failed to divide the communist island from the ideologically aligned Venezuelan leader.

The most recent power outage hit Venezuela at rush hour Monday, leaving millions without basic services such as cellphone service, lights and running water while freezing Caracas' subway and snarling traffic.

WATCH: Power Returns to Parts of Venezuela After Outages Plunged Much of the Country into Darkness

'High-tech' attack

Maduro said the U.S. launched a ``high-tech electromagnetic attack'' to undermine his rule, but he gave no details or evidence linking the power failure to the United States. In March, he blamed U.S. sabotage for a nationwide blackout lasting nearly a week, considered the nation's worst power failure in its history.

Maduro's opponents blame the outages on corruption and inadequate maintenance under two decades of socialist rule launched by the late President Hugo Chavez.

Venezuelan officials also say the U.S. twice within the last week has sent a spy plane into its airspace. In one case, a Venezuelan fighter jet intercepted it, which U.S. officials say put the plane's crew in danger and threatened its mission conducted while flying in international airspace.

Orelis Lehmann rests from climbing the stairs to her apartment in Caracas, Venezuela, July 23, 2019. The elevator was out of service as a result of an outage that began the day before.

Venezuela is a once-wealthy oil nation that is caught in a historic political and economic crisis that has sent at least 4 million residents fleeing, driven by a lack of food and medicine.

Tensions between Venezuela and the United States intensified this year when the U.S. was first among dozens of nations to announce its support of Venezuelan opposition leader Juan Guaido, who in January declared Maduro's last election a fraud and cited his role as leader of the National Assembly as giving him powers to oust Maduro and hold new elections.

U.S. sanctions on Cuba

Cuba said the U.S. plan to overthrow Maduro is a failure and Cuba is unshaken in its support for the Venezuelan leader. The U.S. has been imposing new sanctions on Cuba with the stated purpose of forcing the communist island to cut back its support for Maduro.

U.S. Secretary of State Mike Pompeo ``is trying to disguise the failure of the U.S. plan to intervene in Venezuela with slander and unbelievable excuses,'' Cuban Foreign Minister Bruno Rodriguez said Wednesday after meeting with Russian Foreign Minister Sergey Lavrov. ``Cuba's cooperation with the Bolivarian Republic of Venezuela is unshaken.''

Child Marriage