"Others might sell out, not me", Garcia said in broadcast comments on Tuesday, repeating a phrase he has used frequently as his political foes became ensnared in the Odebrecht investigation.
Garcia, who had repeatedly denied wrongdoing, was 69.
"Let's pray to God to give him strength", Erasmo Reyna, Garcia's lawyer, told journalists at the hospital.
Police arrives outside a hospital where Peru's former President Alan Garcia was taken after he shot himself, in Lima, Peru April 17, 2019.
'At this moment, the patient has been in an operating room at said hospital since 7.10am, ' the ministry said. He said his condition was "delicate".
Outside the hospital, Peruvians gathered outside waiting for more information from doctors and officials.
Corruption cases have reached the highest levels in Peru politics, most notably involving officials and Odebrecht, the Brazilian construction giant that has admitted to spreading some $800 million U.S. in bribes to officials across Latin America, including $29 million in Peru.
- He stood accused of taking bribes from a Brasilian construction company known as Odebrecht during his second term in office.
The massive scandal has brought down politicians throughout Latin America, especially in Peru, where former President Pedro Pablo Kuczynski was detained just last week as part of a money-laundering probe into his ties to the company.
Prosecutors said they believed the former president received more than $100,000 from Odebrecht, disguised as a payment to speak at a conference in Brazil. A hearing is scheduled to take place Wednesday to decide whether to increase his detention to three years. He said that actions leading up to Garcia's arrest appeared to have been carried out irregularly.
Mr Garcia, a skilled orator who has led Peru's once-powerful Apra party for decades, served as the country's president twice.