BUENOS AIRES, Argentina -- President Fernando De la Rua submitted his resignation Thursday, a high-ranking official said, as his government crumbled amid deadly rioting and looting sparked by anger over Argentina's deepening economic crisis.
The resignation followed two days of clashes between police and protesters that left at least 20 people dead and scores injured. On Thursday, police battled hundreds of demonstrators in the streets of Argentina's capital, while looters ransacked homes and supermarkets nationwide.
The resignation must be approved by Congress before taking effect, officials said. Senate President Ramon Puerta was expected to be named interim president when the resignation is finalized.
The official, who spoke with The Associated Press on condition of anonymity, said De la Rua had signed his resignation late Thursday afternoon.
It came amid local reports that De la Rua efforts to cobble together a government of "national unity" with the opposition Peronist Party had encountered resistance.
Earlier Thursday, De la Rua sent riot police to quell the violence after 20 people died across the country in two days of rioting sparked by the government's failure to end a punishing recession marked by double-digit joblessness, hunger and rising poverty.
Authorities arrested more than 2,000 people nationwide, including 350 in the capital. In Buenos Aires, one man was dragged by his hair, others carried kicking and shouting to police vans.
De la Rua's resignation came hours after his economy minister, Domingo Cavallo, quit. Television reports said the entire Cabinet had offered to resign.
De la Rua went on national television Thursday and invited the opposition Peronist Party to join him in a government of "national unity."
"We are in a critical situation," he said. "I share the anguish of our people. Only a government of national unity can lift our country up."
He said he was open to changes in economic and social policies to restore peace and defend the country's democratic institutions.
Earlier in Buenos Aires, protesters fought pitched rock-throwing skirmishes with riot officers, who swung truncheons, charged at the crowd on horseback and fired round after round of tear gas. Water cannons roared across the Plaza de Mayo, directing their jets against scrambling demonstrators, who then counterattacked. Many demonstrators called for the departure of De la Rua.
"Get out! Get out!" the angry crowd shouted over helmeted riot police defending the Casa Rosada, or presidential palace, where the president was reported to be holding emergency meetings.
Defying a state of siege imposed Wednesday by De la Rua, the crowds stood up to hours of rubber bullets, water cannon and repeated charges by cavalry.
The battles raged for hours as white clouds of tear gas wafted over the palm-lined plaza of the elegant European-style capital whose central boulevards dawned grimy and gray, littered by rocks and smoldering trash fires.
The grassy Plaza de Mayo, the downtown square fronting the Casa Rosada, has long been the stage for national protests against the austerity measures taken by the De la Rua government to end the spiraling economic crisis.
The unrest spread across the nation of 37 million people, with looters attacking supermarkets in major cities and ransacking homes. Eight of those killed were in outlying provinces, and many died of gunshot wounds.
Fourteen people died Thursday and six others were killed on Wednesday. The dead included a 15-year-old boy shot Thursday during disturbances in western Santa Fe province, as well as people reportedly shot by merchants defending their stores.
In the Buenos Aires suburb of Quilmes, a 23-year-old man was shot and killed during a pre-dawn supermarket raid by looters. In southern Rio Negro province, a 46-year-old woman was shot to death during
confrontations between police and supermarket raiders.
The anger was sparked by four years of bitter recession that has exhausted the country and left it staring at a possible default on its $132 billion public debt. Unemployment last month reached over 18 percent and industrial production has plummeted.
The government has enacted eight austerity plans and is seeking even further cuts in public spending. It has already faced an equal number of general strikes.
Outside the ornate government palace Thursday, protesters chanting "Come out! Come out!" called for De la Rua to step onto the balcony and face the people. But the shutters remained closed, the palace surrounded by iron barricades and scores of riot police.
"We want him out," said Adrian Gonzalez, 43, waving the blue and white Argentine flag. "We want them all out, not just De la Rua, but all of the political leaders. This is a wake up call: we're fed up with this
country's political class."
After Cavallo's resignation, a federal judge issued an order prohibiting him from leaving the country.
Austerity measures introduced by Cavallo, including a partial freeze on bank withdrawals designed to prop up the financial system, have sparked widespread protests.
On Wednesday night, De la Rua said he was imposing a 30-day state of siege, which gives authorities the right to make arrests without court order and forbids unauthorized public gatherings. It was the first time in 11 years an Argentine president has enforced such a decree.