Guatemala's vice president resigned on Friday to face an investigation over her alleged involvement in a customs corruption racket, amid a scandal that has hurt the ruling party ahead of elections.

President Otto Perez Molina announced the decision after reports linked Vice President Roxana Baldetti to a ring accused of taking bribes to avoid levying customs taxes that was purportedly led by her personal secretary.

Baldetti has denied any wrongdoing, but her chief aide disappeared after joining her on a trip to South Korea in April.

Opposition lawmakers have demanded Baldetti face a probe, and angry Guatemalans have spilled into the streets calling for her resignation.

"This is a personal decision to submit to the needed investigations..." Perez Molina said. "Her decision is personal, thoughtful and courageous."

Around 500 people gathered in the capital's central plaza to celebrate, waving the country's blue and white flag.

"Baldetti's resignation was necessary because we don't want more corruption. Now the government knows that we are not going to tolerate more abuses against the people," said Rodrigo Alvarez, a university student.

Baldetti was elected in 2011 with Perez Molina, a former general who had led forces during the country's three-decade-long civil war that ended in 1996. Their Patriot Party has been hurt by the scandal ahead of a presidential election in September.

The U.S. State Department said in a statement that is supported the government's efforts to fight corruption and urged officials to keep working with a United Nations-backed office that played a key role in the current customs case.

"Strengthening transparency and government accountability is a central element of the Alliance for Prosperity," said U.S. State Department spokesman Jeff Rathke, referring to a U.S. aid plan for Guatemala, El Salvador and Honduras.

Guatemala's Supreme Court this week ruled lawmakers could revoke the vice president's immunity from prosecution.

Twenty-four people, including the country's top tax agent, have already been arrested in the scandal and authorities are looking for Baldetti's former top aide, Juan Carlos Monzon.