Argenis Chávez, brother of the late Venezuelan President Hugo Chávez, has been sworn in as governor of Barinas.
The previous state governor, Zenaida Gallardo, stepped down citing medical reasons.
She had only been in the post since January when she took over from another of Hugo Chávez's brothers, Adán.
Both Argenis Chávez and Ms Gallardo rose to the post through a rule which says that in case the governor steps down, the interior minister takes over.
Mr Chávez had been named interior minister of Barinas only days before being sworn in as governor.
He is taking over as governor at a time when Barinas has been rocked by violent anti-government protests.
Official buildings have been attacked and shops looted by Venezuelans angry at the country's spiralling inflation and shortages of food and medicine.
In a speech at his swearing-in ceremony, Mr Chávez blamed the country's problems on an "economic war" being waged against the government.
"The US empire is trying to overthrow the Bolivarian Revolution and the government through a coup d'etat," he said.
Mr Chávez is expected to be in power at least until December, when long-delayed gubernatorial elections are due to be held.
However, opposition activists say they fear the elections, originally due to be held in December 2016, could be postponed again.