UPDATE 1-Russia's Putin raps tycoons in crisis-hit town

* 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 (Reuters) - 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.