SAN JUAN (WASHINGTON POST) - The governor of Puerto Rico announced late Wednesday (July 24) that he will resign effective Aug 2, amid intense pressure from inside and outside of his government, after a series of leaked chat messages denigrating his opponents and Hurricane Maria victims triggered outrage from frustrated citizens who had taken to the streets for 13 consecutive days of protests.

Mr Ricardo Rossello had defied calls for his resignation as the island descended into upheaval. He lost support from nearly everyone in his ruling statehood party, and more than a dozen members of his administration had stepped down in recent days, including his chief of staff on Tuesday.

On Wednesday afternoon, the leader of the Puerto Rico House of Representatives, Mr Carlos Mendez Nunez, said that an impeachment inquiry by three attorneys concluded that there were legal grounds to begin the process to remove Mr Rossello.

Mr Mendez said that process would start if the governor did not resign and put "a final point on all this."

Mr Mendez's challenge suggested the lawmaker had the necessary votes to obtain a two-thirds majority in his chamber and send the case to the Puerto Rico Senate. Puerto Ricans waited for hours for an answer from their embattled governor as the uncertainty ratcheted up and speculation about his potential successor abounded.

Justice Secretary Wanda Vazquez Garced, who is also the target of intense criticism from the Puerto Rican public, will succeed the governor as the constitutional next-in-line.

Ordinarily, the secretary of state would succeed the governor but Mr Rossello failed to name a new secretary after the previous one resigned for his role in the group text messages.

Ms Vazquez, who was appointed in 2017 to her post - equivalent to a state attorney-general - has faced criminal charges related to her interference with a case involving her daughter and was accused of ethical lapses. She was later cleared of those charges.

A former district attorney in Puerto Rico, Ms Vazquez has been criticised for delaying or mishandling prosecutions of members of her own party. She came into direct conflict with the powerful Senate leader Thomas River Schatz over the indictments of two contractors and one of his staffers in an alleged fraud scheme.

"Vazquez is compromised," said lawyer Mayra Lopez Mulero before Rosselle's announcement Wednesday. "The public would perceive her as an illegitimate leader because of her office's slow response to the chat scandal."

She is expected to be sworn into the office and finish out Mr Rossello's term which expires in 2020 when new elections will be held.

Leaked profanity-laced text messages, written on the encrypted messaging app Telegram, showed Mr Rossello and 11 of his closest aides using sexist and homophobic language to demean female politicians, as well as journalists and Puerto Rican singer Ricky Martin, and making light of Hurricane Maria's victims.

For nearly two weeks, Mr Rossello asked for forgiveness while insisting he would remain in power to finish the work he had started. He promised not to run for reelection and resigned as head of the New Progressive Party, which holds majorities in both the Puerto Rico House of Representatives and Senate.

But what he thought were concessions only inflamed passions and intensified protests across the archipelago. Puerto Ricans of all political ideologies, classes and ages converged for a massive march on Monday that captured international attention as one of largest mobilizations in the territory's history.

Protesters shut down the main expressway in San Juan as the euphoric demonstration spread across more than eight lanes of highway. They called in unison for the governor to resign - "Ricky Renuncia!" - using the diminutive form of his name, Ricardo.

As news of his imminent departure spread late Tuesday, the number of demonstrators outside the governor's mansion in Old San Juan, La Fortaleza - ground zero for the protests - swelled.

Mobile alerts from local news outlets tipping off the impending resignation triggered deafening cheers and incessant clanging of pots and pans late into the night.

The resignation brought joyous relief to the US territory of more than 3 million American citizens anxious, sleepless and enraptured by the turmoil gripping the Caribbean island. The drama of the last 13 days has paralysed civil society and the question of Mr Rossello's political fate has dominated conversations islandwide since the FBI arrested two top members of his administration on public corruption charges earlier this month and 889 pages of the encrypted group chat were unveiled.

There were signs that Mr Rossello's governorship was unravelling.

On Tuesday, his chief of staff Ricardo Llerandi resigned citing threats against his family and the interim director of the Puerto Rico government's federal office in Washington also stepped down, saying the revelations of the chat contradict his personal values and ethics.

Then, a Puerto Rico judge issued search warrants for the cellphones of the government officials involved in the private group text. It is unclear if the devices have been turned over to authorities.

Some of governor's mayoral allies became the latest to ask for Mr Rossello's resignation. Guaynabo mayor Angel Perez Otero spoke to the governor and explained that the government's paralysis would have grave consequences for the island economy.

"I indicated to the governor that it was time," said Ms Otero, a member of Rossello's party. "For his family and the peace of the people, it was time to leave and allow a peaceful transition so Puerto Rico can get back to normal."

Puerto Rico's Resident Commissioner Jennifer Gonzalez said her colleagues in Congress are concerned that the high level departures in Mr Rossello's government will delay and paralyse pending recovery efforts, projects and federal fund distribution.

"This has been not just a distraction, it's been incredibly worrisome," said Ms Gonzalez, who endorsed a plan to appoint a federal coordinator to oversee and assure disaster aid is distributed where it's needed most, similar to what was done in New Orleans and New York during Hurricanes Katrina and Sandy.

"We need to get out of this morass because the people of Puerto Rico have endured too much."

The Federal Oversight and Management Board, which is restructuring the island's estimated US$74 billion (S$100.99 billion) debt and has control of its finances, had avoided comment on the political crisis.

But on Tuesday afternoon, the board issued a statement that said it hopes the political process "swiftly resolves the current governance crisis" and that elected officials have a "responsibility to restore integrity and efficiency."

The board continued to say that, "for far too long government in Puerto Rico has failed to treat the island's residents with the respect that they deserve" and "elected officials and government employees must understand and accept that their job is to serve the people of Puerto Rico, not insiders, special interests or their own political careers."

Later on Tuesday, the governor appeared on Fox News Channel for the second day in a row saying that, "I will always do what's in the best interests of the people of Puerto Rico."

In a written statement Tuesday, he said, "When the people are speaking, it's my job to listen."

But with each rumour that resignation was imminent, Mr Rossello frustrated and the people trembled. The governor called a hasty news conference and kept the press corps waiting for more than two hours for news that news was coming. The public affairs secretary - one of the last men standing in Mr Rossello's corner - said the governor would speak directly to the people Wednesday.

No time was given. The content of the message was unknown. And as the night dragged on and the promised pronouncement did not come, thousands of protesters grew louder and police reinforcements went into formation.

The son of a former governor, Mr Rossello is a member of a ruling elite and moneyed political class that has long wielded power in Puerto Rico and supports making the territory the 51st US state.

He attended private school in Guaynabo, a posh San Juan suburb know for its gated communities and influential residents, and studied biomedical engineering at MIT and earned a doctorate from the University of Michigan.

He swept into the 2016 election, promising statehood and offering himself as the antidote to Puerto Rico's persistent economic and political afflictions. He captured little more than 40 per cent of the vote in an election with one the lowest participation rates in the island's history, evidence of an unusually disenchanted electorate, historians said.

Congressman Raul Grijalva, who chairs the House Natural Resources Committee that oversees US territories, said the resignation was "long overdue" for Puerto Rico to take the next steps.

"The people of Puerto Rico have shown the world what can happen when a united public demands justice and accountability with a clear voice," he said in a statement. "Now they must choose what comes next, and Congress must listen."