"The party gave us permission to vote and withdraw the president's immunity," said Luis Fernandez Chenal, a lawmaker with Perez Molina's ruling party. "He who owes nothing, fears nothing."
About 200 people outside the capitol cheered and set off firecrackers upon hearing news of the vote.
"Excellent! It is a step forward for Guatemala," said Gerardo Corzo, a 71-year-old retiree.
The customs graft scandal has already claimed the job of Perez Molina's former Vice President Roxana Baldetti, who is in jail awaiting trial on accusations she accepted millions in bribes in return for letting others avoid import duties. A number of Cabinet officials have also left office.
Massive protests have demanded Perez Molina resign and a postponement of this coming Sunday's elections, but he has refused to do so. Perez cannot run for re-election and is set to remain in office until a handover in January.
"This decision demonstrates that the people and their collective actions can get results, but this is just the beginning," said activist Byron Garon. "Now we want him and his vice president to be tried and convicted, and for them to give back to Guatemala all that they stole."
Adriana Beltran, a Guatemala analyst at the Washington Office on Latin America, said the investigations and Tuesday's vote send a "remarkable" message to Guatemalans about political reform and the rule of law: "That you can make it work following due process and respecting human rights, and that those that at one point were considered untouchable can be brought to justice."
Earlier in the day, civilians formed a wall of bodies to let lawmakers into Congress, protecting them from dozens of presidential loyalists who had blocked access to the capitol since the morning in a bid to delay the proceedings.
Interior Department Vice Minister Elmer Sosa also arrived with riot police to "guarantee the safety of protesters and Congress," and lawmakers were finally able to go inside and begin the session.
"It was impressive that the people themselves came and created a human chain and a path so we could enter," said opposition legislator Leonel Lira.
Government agents have had to step in on several occasions to keep backers and critics of the president away from each other.
The Associated Press
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