"Yesterday's illegitimate elections confirm that Maduro is a dictator who disregards the will of the Venezuelan people", Mnuchin said in a statement.
Maduro's response was to initiate a rewriting of the constitution put in place in 1999 by his predecessor Hugo Chávez. "Why would so many people be voting if it was merely symbolic?" he said, describing the vote as the Venezuelan population's endorsement of the Bolivarian government that has been continuously democratically elected and certified by the worldwide groups who have monitored their elections", he continued.
"This is the end of freedom of expression, and this freedom has been battered for some time now", said Attorney General Luisa Ortega.
Antonio Ledezma and Leopoldo Lopez were serving house arrest in their respective homes in Venezuela's capital, when agents bearing the acronym of Venezuela's security services Sebin on their clothes detained them in overnight raids.
The measures were unusual in that they targeted a sitting head of state, but their reach was mostly symbolic, freezing any USA assets Maduro might have and banning people under U.S. jurisdiction from dealing with him.
External pressure is growing, but of mixed effectiveness. According to him, Venezuela woke up on Monday, "the more divided and isolated from the rest of the world". Although many neighbouring countries have said they will not recognize the results of the weekend's vote, others - including Cuba, El Salvador, Nicaragua and Bolivia - have expressed their support for Maduro.
Surveys by polling firm Datanalisis showed more than 70% of Venezuelans opposed the new assembly.
"I obeyed orders as imperialist, I do not obey not to foreign governments, I am a president free", said Mr Maduro in a televised speech.
Frank Sinatra's Widow, Barbara, Dies At 90
The center was founded by Barbara and Frank Sinatra in 1986, and was established to aid "abused, neglected, and at risk children". Barbara became involved in supporting and raising funds for a number of charitable projects years after she married Sinatra.
Marczak recalled that the USA recognized the fleeting government of Pedro Carmona after a 2003 coup against Chavez that ultimately failed.
Several governments recognized the outcome, but Maduro ignored it.
The Trump administration already levied sanctions on two dozen current and former government officials since taking office, but the strategy so far has failed to alter Maduro's iron-fisted rule. "We hold the regime responsible for his life and physical integrity".
"It may mean more targeted sanctions at individuals". This is now being discussed, but the pain would be felt across borders.
Venezuela has been engulfed in an economic crisis, featuring skyrocketing inflation and food shortages. Such a move would probably cause a fresh wave of refugees to neighbouring countries.
In recent months, protesters have flooded the streets of Venezuela as clashes have turned violent, with more than 100 people killed in the chaos. For Trump - who promised lower gas prices at the start of his administration - this would be another political own goal.
Venezuela remains under political unrest in the aftermath of a widely disputed election for a new Constituent Assembly that will replace the democratically elected members of the country's opposition-dominated legislature.