Puerto Rico's scandal-scarred governor, Ricardo Rosselló, said Sunday that he won't resign but that he will step down as head of his party and won't seek re-election in 2020.

"Saying sorry is not the only thing I can do," Rosselló said in a live address, saying he knew "I have to work" to regain islanders' trust.

Rosselló's remarks came a day before a massive demonstration on Monday, which some expect to be the largest in the U.S. territory's history. All major shopping centers as well as some other establishments and offices have closed, and the rally and march will go through one of the main highways in the San Juan metro area. High-profile celebrities like Ricky Martin, the singer Kany García and Benito Martínez, the rap artist known as Bad Bunny, will be taking part.

Already, hundreds of thousands of Puerto Ricans have taken to the streets demanding that Rosselló resign after corruption investigations and 889 pages of private chats between him and some of his officials and close associates were leaked.

The leaked chats included profanity-laced, misogynistic and homophobic comments, as well as barbed and cynical remarks about a variety of topics, including the deaths following Hurricane Maria in 2017.

Members of the chat group, which used the encrypted messaging app Telegram, made fun of an obese man whom the governor had posed with in a photo, called former New York City Council Speaker Melissa Mark-Viverito a "whore" and made homophobic remarks about the pop star Ricky Martin.

In one of the messages, Rosselló said that San Juan Mayor Carmen Yulín Cruz, who has announced that she plans to run against Rosselló in 2020, was "off her meds ... either that, or she's a tremendous HP," using the Spanish initials for "son/daughter of a b----."

Rosselló has said the messages were private remarks made to blow off steam after long days. But top island officials, including members of his own party, have been highly critical and gave the governor a deadline to "reflect" and prove that he should stay in office.

Legislators are considering his impeachment. The newspaper El Nuevo Día reported Sunday that House Speaker Carlos "Johnny" Méndez last week began putting together a legal team to explore the possibility of an impeachment process. Rosselló said he welcomes the legislative probe.

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