epa12049407 Mexico's President Claudia Sheinbaum speaks during a press conference at the National Palace in Mexico City, Mexico, 23 April 2025. Sheinbaum asked the Electoral Tribunal to invalidate candidates in the first popular election of the Judiciary who have ties to drug trafficking after the Senate recognized that there are aspirants with these links. EPA/MARIO GUZMAN 
Alejandro "Alito" Moreno, head of the opposition Institutional Revolutionary Party (PRI), came at senate president Gerardo Fernandez Norona, of the ruling Morena party, as lawmakers were singing the national anthem to mark the end of the day's hearing.
The fight broke out after a "difficult debate" about the presence of armed forces from other countries in Mexico, Fernandez Norona later told a press conference.
In livestreamed video, Moreno could be seen coming up to Fernandez Norona, repeatedly saying, "I'm asking you to let me speak," grabbing Fernandez Norona by the arm.
"Don't touch me," Fernandez Norona responds.
Finally, the two begin to push each other, with Moreno knocking over a photographer in the process.
Another lawmaker also entered the fray, swinging at Fernandez Norona as he tried to step away.
"(Moreno) started pulling on me, touching me, pushing. He hit me and said, 'I'm going to beat the shit out of you, I'm going to kill you'," Fernandez Norona said.
Fernandez Norona said he would call an emergency session for Friday and would propose expelling Moreno and three other PRI lawmakers for the fight.
Moreno said Fernandez Norona had swung at him first.
(Reporting by Kylie Madry; Editing by Stephen Coates)