ROME (AP) – Silvio Berlusconi resigned Wednesday as premier but vowed to quickly form a stronger new Cabinet to restore confidence in his leadership.

Resigning and then immediately shuffling the Cabinet is an old trick of Italy’s complicated political system, and has been used by premiers to strengthen faltering coalitions.

Berlusconi, who had presided over Italy’s longest-serving government since World War II, had so far resisted the move, sensing it would dent his image as a new-style politician.

But the resignation, which he submitted to the president, is expected to enable Berlusconi to form a more solid Cabinet after weeks of infighting within his coalition.

It is formally up to President Carlo Azeglio Ciampi to designate a candidate to assemble a new government, or dissolve parliament and call early elections.

Ciampi is expected to give Berlusconi the mandate to form a new Cabinet.

Berlusconi, who is staying on as caretaker, was quoted as saying by the Apcom news agency that he expects the government crisis to be over by the end of the week.

He reportedly said he will not change many ministers, but did not give details.

The resignation was welcomed by his allies, who had demanded it after the electoral defeat.

“Premier Berlusconi has been good. His speech was excellent,” said Gianfranco Fini, who serves as deputy premier and foreign minister.

Fini’s party, the National Alliance, had threatened to quit the government Tuesday. Such a move by the second-largest coalition partner, following the withdrawal of a smaller coalition ally, would have thrown the Cabinet into further chaos.

Berlusconi’s popularity has been sagging. Though his resignation was a personal defeat, the ever-smiling billionaire had his usual confident and winning tone during the Senate address.

“I believe we have carried out things of great importance over these years of economic reforms, institutional reforms and implementation of our foreign policy,” he said. “We have put an end to the permanent instability of our system. We have increased Italy’s role and international prestige.”

Berlusconi appeared to appease some requests from his allies when he said the new platform would focus on aiding Italy’s underdeveloped south and financially pressed families.

The economy is high on the list of worries. Last year, Italy’s economy expanded by 1.2 percent, compared to an average of 2 percent in the entire 12-nation euro zone, and the government is under pressure from the European Union to contain its ballooning deficit.

The center-left opposition has been pressing for early elections, confident that it might be able to oust the conservatives from power as recent polls have suggested.

“If having a carbon copy of the government is the idea, it’s better to give voters their say,” said opposition leader Piero Fassino.

The center-left, like a majority of Italians, opposed Berlusconi’s decision to send 3,000 troops to Iraq after the ouster of Saddam Hussein.

Pressure to pull out the troops mounted after the March 4 killing in Baghdad of an Italian intelligence agent who was escorting a released hostage. The agent was shot by U.S. troops who mistakenly fired on his vehicle.

AP-ES-04-20-05 1745EDT