MILAN, Italy - Alitalia is hanging out a "For Sale" sign yet again.

The bankrupt airline is publishing a notice in four newspapers Tuesday seeking offers to buy any or all parts of its assets.

The move comes a day after a group of Italian investors officially confirmed a decision to withdraw its offer to take over Alitalia's profitable assets.

It was the third failed attempt to sell off the long-troubled airline in less than two years as two successive governments have moved to keep a four-year-old pledge to the European Union to privatize the flagship carrier.

The sales notice, published Monday evening on the airline's Web site, urges potential buyers to take into account the need for a speedy transaction.

Barring a valid offer, Alitalia's extraordinary administrator, appointed after the airline declared bankruptcy Aug. 29, said Alitalia's clock would stop ticking Oct. 1.

Italian civil aviation authorities have indicated it might be even sooner.

"I would say that we have until the end of the week," administrator Augusto Fantozzi told reporters in Rome on Monday. "Probably we will have time until next Tuesday, which means in effect that, as of today, Sept. 30th is the last day possible" of operation.

He acknowledged that the airline's chances for survival looked bleak.

"There are no prospects for a rescue in a reasonable time," Fantozzi told reporters.

The government has already made clear that the offer by the group of Italian investors led by scooter-maker Piaggio chairman Roberto Colaninno was the last best chance for Alitalia's survival.

The group had pledged to inject $1.4 billion into the bankrupt airline, sell off unprofitable assets and merge the rest with Italy's No. 2 carrier Air One. But the deal - like the offer by Air France-KLM last spring -- was withdrawn amid union objections.

Labor Minister Maurizio Sacconi repeated Monday that all major European carriers who could be potential buyers have been solicited -- and have said thanks, but no thanks.

Italian aviation authorities, meanwhile, warned that Alitalia could be grounded within days if no deal is reached to sell the bankrupt airline.

"By Thursday, Alitalia's bankruptcy commissioner must come up with a credible plan to avoid the revocation or suspension of the flight license," the agency's chief Vito Riggio said after meeting with Fantozzi. ENAC officials would then take two or three days to study the plan, he said.

ENAC in a statement later said that any rescue plan must be "realistic" and that the agency is monitoring Alitalia's safety situation daily. ENAC wants to verify the airline can fulfill European Union requirements, such as having enough money to ensure refueling, maintenance and safety.

The agency said Fantozzi himself might seek the suspension of flights if no concrete deal materializes.

"For the time being, flights are regular, the financial situation is difficult, but we will wait until next week before taking any decision," Fantozzi told Associated Press Television News.

Fantozzi said that this month's payroll, due Sept. 27, will use up much of what little cash Alitalia has left.