Umberto Bossi, the longtime ally of former Italian premier Silvio Berlusconi, says his Northern League party won't back any government led by economist Mario Monti "for now."
Bossi says he told Italy's president that his party will be a "vigilant" opposition to any Monti government until the economist spells out his program to rescue Italy's troubled economy.
Berlusconi resigned Saturday after Italy came under enormous pressure for its sovereign debt.
Bossi says "for now, we said no." He adds when Monti reveals his policies, the League will decide on a measure-by-measure basis.
Italy's president could ask Monti to try to form a government to rescue Italy from looming financial disaster after talks with all parties Sunday.
THIS IS A BREAKING NEWS UPDATE. Check back soon for further information. AP's earlier story is below.
ROME (AP) -- Italy's president began sounding out political leaders Sunday on whether to ask economist Mario Monti to try to form a government, a day after Silvio Berlusconi resigned with the nation on the brink of financial disaster.
Giorgio Napolitano was holding back-to-back meetings as he seeks to establish whether Monti, the highly respected former European Union competition commissioner, or another contender can garner enough support to form a government and rescue Italy from looming economic doom.
His decision could come as soon as Sunday evening. Italy faces severe pressure from the financial markets to have a government named by Monday morning when the work week resumes.
Monti was his typical polite and reserved self when journalists spotted him and his wife leaving their Rome hotel to head to church. Asked whether he was excited at the prospect of being Italy's next premier, he responded: "Have you noticed what a beautiful day it is?"
Napolitano, who is head of state, received parliamentary and party leaders at the Quirinal presidential palace. After heads of the smaller parties in Parliament have their turns, the bigger parties -- including Berlusconi's splintering conservatives -- will meet him in late afternoon and early evening.
Roberto Maroni, a founder of the Northern League, whose support kept Berlusconi in power, said Sunday that his party will be in the opposition during any Monti government.
"I personally esteem Mario Monti, a great person," Maroni told Italy's Sky TG24 in an interview. "But Parliament must have the guarantee of an opposition. Otherwise it won't be a democratic parliament."
Maroni, the outgoing interior minister, said the League's lawmakers will decide on whether to back legislation, measure by measure. "The League wants to be able to "oppose any maneuver that goes against our interests."
Pressured by day after day of poundings by the markets, which lost faith in the once charismatic leader, Berlusconi stepped down Saturday night as promised, as soon as urgent anti-crisis measures won final approval in Parliament. He slipped out of the presidential palace through a side door after handing Napolitano his resignation, as a hecklers jeered in the square outside the main entrance.
Maroni said he spoke with Berlusconi Saturday night and found the usually ebullient media mogul "very tried, physically tired. But he is always a great fighter."
"It was an ugly show to see. People spitting, throwing" objects, Maroni said of the hecklers.
"This phase is over, a blank page is being opened," Maroni said, holding out hope that the League and Berlusconi's forces might again join in a future political coalition. The League is pressing for elections earlier than their spring 2013 due date.
Berlusconi's longtime nemesis, former anti-corruption prosecutor Antonio Di Pietro said that his small Italy of Values Party would be willing to back a strictly "technocrat" government with no politicians in the cabinet "to respond to the (economic) emergency and give back this country its credibility."
Without mention Monti by name, Di Pietro insisted after meeting with Napolitano that elections must be held as soon as possible. But, he acknowledged, "in these hours of emergency, it's very hard" to carry out an electoral campaign.
Several leaders in Berlusconi's own conservative party have openly said they either want the outgoing premier's political heir, Angelino Alfano, or some Italian veteran politician like former premier Lamberto Dini.
Most centrists and center-left parties in the opposition have pledged their support for a Monti government, saying he has the moral authority and economic know-how to implement the measures and finally start Italy on a path of long-delayed structural reforms of its flat economy.
Napolitano unexpectedly propelled Monti into the political limelight when he named him senator-for-life last week, putting the economist suddenly in Parliament.