Several of Venezuela’s leading opposition figures, facing arrest warrants, have been in hiding at the Argentine diplomatic residence in the capital, Caracas, for more than eight months, where they have sought asylum.

Now, four months after July’s tainted presidential election in which President Nicolás Maduro declared victory without providing any evidence, the authorities are cutting off the residence’s access to electricity, water and food, according to Tomás Arias, a lawyer for the opposition group.

The six people played various key roles for the Venezuelan opposition, including helping to organize its presidential campaign.

The move by the Venezuelan authorities reflects a ratcheting up of antagonistic measures by the autocratic government that analysts say is meant to deliver a clear message that Mr. Maduro, who is scheduled to be inaugurated next month, intends to stay in power.

Mr. Maduro, who has a long history of rigging elections in his favor, analysts say, declared victory against Edmundo González, a diplomat who had the backing of the country’s popular opposition leader, María Corina Machado.

The president has not released the official vote tallies to back up his claim, while those released by the opposition show that Mr. Gonzalez was the clear winner.