Police broke up a fuel depot blockade in France on Wednesday and France's hardline CGT union prepared for a strike at a nuclear plant, escalating a standoff over proposed new labour laws.
France has also mobilised its emergency motor fuel stocks for the first time since 2010, a spokeswoman for oil lobby group UFIP said.
Ministers went on radio morning shows to say the government would stand firm, while CGT chief Philippe Martinez told RTL radio that his union, one of the most powerful in France, would press on with its strikes.
At stake is a labour reform that the government says is crucial to fight rampant unemployment stuck at over 10 percent of the workforce and which aim to make hiring and firing easier. The CGT says the reforms will unravel protective labour regulation, even though other unions back it.