AGEN, FRANCE - A US construction equipment maker has agreed to pay extra money to laid-off workers at a French branch who had threatened to blow up gas canisters at the plant, officials said Friday.

Staff at JLG Industries, a subsidiary of US firm Oshkosh that makes lifting equipment and work platforms, were the third group of French workers to threaten force to back demands for better redundancy pay-offs.

Striking workers had positioned a ring of gas canisters - empty according to local gendarmes - round five brand new lifts, removing them when managers agreed to talks, a tactic denounced as "blackmail" by the government.

"We were proposing compensation of 30,000 euros (42,000 dollars) above the legal minimum, for the 53 people who are going to lose their jobs," said Christian Amadio, head of the works council at JLG in southwestern Tonneins.

"We obtained what we were asking for," he said, adding that a deal was signed overnight with management. "It's shame we had to go so far to obtain a result."

Seen as a last-ditch bid to attract media attention and put pressure on their employers, the threats follow a wave of "bossnappings" in which French workers took their managers hostage over factory closures.

Seven workers from auto parts maker Continental were on trial Friday for trashing a regional government office in April, in another violent outburst over the closure of a factory north of Paris with the loss of 1,120 jobs.

French Employment Minister Laurent Wauquiez raised the tone over the blast threats Thursday, accusing the workers of "blackmail."

But the government has stopped short of sending in police, saying it understands the distress of workers hit by the recession - suggesting it sees the radical tactics as a media stunt rather than a serious threat.

Carmaker Renault refused Thursday to meet the demands of workers at a bankrupt car parts supplier, New Fabris, who threatened at the weekend to blow up gas canisters inside their factory in western Chatellerault.

Workers at New Fabris want Renault and PSA-Peugeot - who accounted for 90 percent of their business - to pay 30,000 euros to each of the 366 laid-off employees.

Renault and Peugeot have said it is not their responsibility to pay compensation to the workers.

Renault offered Thursday to buy up the stock of parts that were intended for it, and for the proceeds to be paid to New Fabris workers, but unions rejected the offer, which they estimated at 3,000 euros per head.

Laid-off workers at telecoms firm Nortel Networks near Paris made a copycat threat on Monday, briefly threatening to blow up their factory before backing down the following day.