With the state House of Representatives in Austin preparing to adjourn, a bystander's video showed one lawmaker appearing to shove a colleague as about a dozen others rushed together in an angry clutch before tempers cooled and the two sides separated.
Afterward, one of the legislators at the center of the confrontation said in a statement on Facebook that he was physically assaulted by a Democratic colleague while a second Democrat threatened his life.
Republican Matt Rinaldi's statement said this occurred after he told Democratic lawmakers that he had tipped off federal agents about defiant protesters who were holding signs declaring their illegal immigration status.
Rinaldi did not immediately return calls or emails seeking further comment.
The incident highlights the raw emotions stirred by Republican efforts to put Texas in line with the priority that President Donald Trump has given to combating illegal immigration. Democrats, mostly representing urban centers that have defied federal policy, have condemned the crackdown.
Texas, which has an estimated 1.5 million illegal immigrants and the longest border with Mexico of any U.S. state, has been at the forefront of the immigration debate.
It also allows police to ask people about their immigration status during a lawful detention, even for minor infractions like jay-walking.
Democrats have warned that the Texas law could lead to unconstitutional racial profiling. Civil rights groups have promised to fight it in court.
(Reporting by Alex Dobuzinskis in Los Angeles, Editing by Frank McGurty and Dan Grebler)
(This story has not been edited by NDTV staff and is auto-generated from a syndicated feed.)