Rival deputies scuffled on the floor of Mexico's Congress on Tuesday (November 28) as leftist lawmakers tried to take the podium to protest President-elect Felipe Calderon's inauguration this week. 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. The leftists said they would not leave. Some analysts fear Calderon will be forced to hold Friday's (December 1) ceremony at an alternative site. Leftists from the Party of the Democratic Revolution, who say Calderon won July's presidential election by fraud, have vowed to prevent the conservative from being sworn in. Calderon is expected to be a key U.S. ally in Latin America, where Washington's influence has been hit by a series of left-wing gains in recent years. The leftists and lawmakers from Calderon's National Action Party pushed and shouted at each other in the chamber of deputies. The speaker of the chamber, Jorge Zermeno, suspended the session. Mexico has been divided politically since the election, which Calderon won by less than one percentage point. Losing candidate Andres Manuel Lopez Obrador has declared himself Mexico's "legitimate president" and vows to hound Calderon, a former energy minister in outgoing President Vicente Fox's government. Calderon's razor-thin presidential election victory split Mexico along class lines six years after President Vicente Fox ended 71 years of one-party rule. Andres Manuel Lopez Obrador, the losing left-wing candidate, claimed massive fraud and paralyzed central Mexico City for six weeks with protest camps. Earlier on Tuesday, Mexican President-elect Felipe Calderon named a hard-line conservative for interior minister. 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.