Mexican representatives clashed have clashed in Congress in a deepening political crisis days before President-elect Filipe Calderon takes power.
Calderon faces open hostility from left-wing parties who claim he stole the July 2 presidential election and have vowed to prevent him from being sworn in on Friday.
In the lower house of Congress , rival deputies upturned furniture, punched and shoved each other and vied for control of the main podium, where Calderon is due to be sworn in.
The standoff carried on into the night, with lawmakers chanting insults, draping banners across seats and bringing sleeping bags and tents into the chamber.
Some analysts fear Calderon will be forced to hold Friday's ceremony at an alternative site.
Calderon is expected to be a key US ally in Latin America, where Washington's influence has been hit by a series of left-wing gains in recent years.
Although Calderon has promised to work with opposition parties to ease months of tension, his appointment of hard-line conservative Ramirez Acuna as interior minister drew immediate fire.
"He's a fascist. We are going to see more repression," said Gerardo Fernandez, spokesman for the leftist Party of the Democratic Revolution.
Ramirez Acuna, 54, was governor of the conservative western state of Jalisco, where he was often criticized for being too eager to use state police to crack down on protesters.
Calderon said Ramirez Acuna has shown he is open to dialogue but also has "an irrevocable responsibility to uphold the law."
The new interior minister is expected to take a hard line in Oaxaca. Six months of protests against the state's governor have brought chaos to the picturesque state capital. About 15 people have been killed, mostly shot by what protesters say are off-duty policemen.
Andres Manuel Lopez Obrador, the losing left-wing candidate, claimed massive fraud and paralyzed central Mexico City for six weeks with protest camps.
Calderon, 44, had to announce the appointment of Ramirez Acuna and other cabinet members at a plush hotel to avoid protests by Lopez Obrador supporters outside his office.
Outgoing President Fox had made those reforms his top foreign policy goal but the efforts failed. Instead, U.S. President George W. Bush last month approved hundreds of miles of new fencing on the border to help keep immigrants out.