Venezuela's opposition on Thursday asked prosecutors to investigate a fight on the floor of congress that injured several opposition lawmakers and forced at least one of them to undergo surgery.

Congressman Julio Borges, who suffered head injuries when ruling party member Michelle Reyes repeatedly struck him in the face, met with federal prosecutors to demand the probe into who was responsible for Tuesday's clash in the National Assembly.

"We were brutally attacked," Borges said, even as government officials argue that opposition lawmakers at least provoked the violence.

The Prosecutor's Office did not comment on Borges' demands and Prosecutor General Luisa Ortega is widely considered to be a close ally of prominent ruling party members and prosecution of lawmakers would be nearly impossible because the legislators enjoy immunity from most criminal charges.

One of the injured lawmakers, Maria Corina Machado underwent surgery Thursday on a nose she said was broken when political rivals threw her to the floor and repeatedly kicked her in the face.

National Assembly president Diosdado Cabello has blamed opposition lawmakers for the violence because they blew whistles and air horns and unveiled a protest banner during Tuesday's session after Cabello refused to permit them to speak.

The opposition is challenging the official result of the April 14 election presidential election narrowly won by President Nicolas Maduro. Cabello has argued that means the opposition lawmakers do not accept their own election under the same system, and has blocked some of their legislative rights.

Before the session began, opposition politicians discovered that microphones had been removed from their desks.

"The worse crime isn't the attack, it's denying the right to speak," Borges said.

The violence inside the assembly has raised concerns abroad.

Jose Miguel Insulza, secretary-general of the Organization of American States, said in a statement that violence unleashed inside the assembly "dramatically reflects the absence of political dialogue that could bring about tranquility."

Insulza has urged President Nicolas Maduro to take measures to "re-establish the inalienable right of lawmakers to freely express themselves."

During a televised speech on Thursday, Maduro accused opposition lawmakers of provoking their colleagues from the ruling party.