* Putin humiliates once-mighty oligarch in public
* Premier hands out tongue-lashing to Deripaska, businessmen
* Move comes as business leaders gather in St Petersburg
(Pvs MOSCOW, Adds details, spokesman's quote, background)
By Oleg Zagoruyko
PIKALYOVO, Russia, June 4 Russian Prime Minister Vladimir Putin publicly humiliated a top oligarch on Thursday, accusing him and other factory owners in a crisis-hit town of greed and likening them to "cockroaches".
Putin, playing on the anger of protesting workers in the town of Pikalyovo, forced Oleg Deripaska, a top metals tycoon and once Russia's richest man, to sign a contract for supplies to help idle factories restart operations.
"You have made thousands of people hostage to your ambitions, your lack of professionalism -- or maybe simply your trivial greed," Putin told Deripaska and two other businessmen who own cement and alumina factories in the town.
"Where is the social responsibility of business ?", he said in the confrontation broadcast on national television.
Putin travelled to Pikalyovo, where hungry workers blocked a motorway this week to protest over unpaid salaries, as world business leaders gathered for Russia's premier annual economic summit in St Petersburg, 270 km (170 miles) away.
He rounded on Deripaska and the two other businessmen, making a veiled threat to expropriate their property unless they sorted out the situation quickly.
"Why was everyone running around like cockroaches before my arrival? Why was no one capable of taking decisions?" Putin said as Deripaska stared blankly.
"Has Oleg Vladimirovich (Deripaska) signed? I do not see your signature. Come here and sign it," Putin said, throwing a pen dismissively onto the table.
His head hanging low, the once-mighty oligarch walked up to the premier's table, read the document covering raw material supplies to the factories and added his signature.
After the meeting, workers cheered Putin and shouted "Hurrah" as he told them the problems at the plants had been resolved. Putin's spokesman Dmitry Peskov said the premier had been "quite strict".
"The signal here is simple. The crisis and other difficulties cannot serve as an indulgence from social responsibility and you cannot solve your problems without taking care of people, you cannot try to put all responsibilities on the shoulders of the state," Peskov said.
"They (businessmen) were not thinking about people at all. There was no hot water, heating, people were not working and were not getting their salaries..."
RESIDENTS IN POVERTY
Residents in Pikalyovo called on the authorities to intervene after all three factories in the town halted work and stopped paying full wages. Trade unions say about half the 23,000 inhabitants of Pikalyovo are living in poverty.
Russia is facing its worst recession in a decade and has 7.7 million unemployed, raising fears of unrest and threatening Putin's main legacy in his previous role as president, eight years of steadily rising prosperity.
Putin also told the businessmen to clear debts of 41 million roubles ($1.33 million) by the end of the day and threatened nationalisation unless the factories' owners solved the problems.
"If the owners cannot agree among themselves, then the ... complexes will be restarted anyway," Putin said. "If you cannot agree among yourselves it will be done without you."
Lawmakers from Russia's ruling party on Wednesday had introduced a bill to nationalise the three factories. It was not clear whether that legislation would go forward.
Deripaska, last year estimated by Forbes to be worth $28 billion, has lost most of his fortune in the crisis and is trying to restructure billions of dollars of loans owed by his flagship company UC Rusal to Western creditors.
UC Rusal, in which Deripaska is the largest shareholder, is the world's biggest aluminium producer. (Writing by Michael Stott and Conor Humphries; editing by Richard Balmforth)