Among the new leaders were Mr. Maduro’s wife, Cilia Flores; the president’s son, Nicolás; Diosdado Cabello, a powerful former military chief who participated in a coup in the 1990s with Mr. Chávez; and a radical television show host known for broadcasting embarrassing recordings of opposition politicians.
Before the ceremony, crowds of government supporters surrounded the Capitol, many dressed in red, the color of Mr. Maduro’s Socialist party, waving flags and dancing to salsa music on speakers. The festive atmosphere was in marked contrast to the months of antigovernment protests and clashes that have left more than 120 people dead and to the hardships faced by Venezuelans dealing with shortages of food and medicine.
On Friday, Mr. Maduro urged assembly members to move swiftly to resolve these problems.
“The mandate of this constituent assembly is to use its powers to make peace, to construct peace, for a new economic model,” he told supporters.
Mr. Maduro’s own authority under the assembly — which is technically above the president — was a cause of speculation among some analysts in recent days, who noted that the president’s rivals within his party might try to take control of the assembly and sideline Mr. Maduro.
But the choice of Ms. Rodríguez, a trusted deputy of the president, to lead the assembly signaled that Mr. Maduro aimed to maintain a firm grip over the assembly’s decisions. Another pick for a leadership post was Aristóbulo Istúriz, a former vice president who had been involved in past talks with the opposition, suggesting that the party’s more radical figures were being kept from the top jobs.
The fate of the National Assembly, the opposition-controlled legislature, was unclear on Friday. Many members of the constituent assembly have called for the legislature to be dismantled, or even for its lawmakers to be jailed. Several countries sent their ambassadors to join the Venezuelan legislators’ sessions, fearful that their chamber would be overrun by force.
But the assembly on Friday chose not to gather in the National Assembly’s chamber, but rather in an adjoining hall in the Capitol, leaving open the possibility that the dueling government branches may — at least for now — coexist.
Elsewhere in Caracas, the capital, a number of supporters of the opposition marched to protest against the constituent assembly and were met by government forces who beat them back. At least one lawmaker was injured,…