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 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.