PARIS (Reuters) - France's hardline CGT union sought to choke off power and fuel supplies and hamper the public transport network on Thursday in a showdown with a government that flatly refused to withdraw a contested labour law reform.
As tens of thousands of demonstrators took to the streets, workers responded to the union call by stopping work at oil refineries, nuclear power plants and the railways, as well as erecting road blocks and burning wooden pallets and tyres at key ports like Le Havre and near key distribution hubs.
The standoff, which raises the spectre of disruption during the France-hosted European football tournament that opens on June 10, was condemned both by Socialist Prime Minister Manuel Valls and the country's other big trade union, the CFDT.
After months of rolling protests sparked by a reform that aims to make hiring and firing easier, Thursday's stoppages and street marches were being watched closely as a test of whether the CGT-led opposition is solid or at risk of fizzling out.
The street marches were joined by scores of marchers from a youth protest movement called Nuit Debout (Up All Night). Police deployed to counter risks of the severe fringe violence in which 350 police and several protesters have been hurt and more than 1,300 arrested at similar rallies in recent weeks.
CGT chief Philippe Martinez, asked by Reuters if his union was willing to disrupt the Euro 2016 football contest, said: "The government will has the time to say 'let's stop the clock' and everything will be ok."
"There is no question of changing tack, even if adjustments are always possible," said Valls, who flatly rejected calls to scrap the part of the law that put the CGT on the warpath.
That section would let companies opt out of national obligations on labour protection if they adopt in-house deals on pay and conditions with the consent of a majority of employees.
The SNCF state train company said that upwards of two-thirds of national, regional and local rail connections were operating, suggesting stoppages by railworkers were hurting less than last week when a similar strike halved the number of trains running.
After police intervention in recent days to lift blockades at refineries and fuel distribution depots, Valls said 20-30 percent of fuel stations were dry or short of certain fuels.
"The situation is less worrisome as of today," Transport Minister Alain Vidalies said. Deliveries of fuel from depots to the petrol pump were now improving, he said.
The number of fuel stations short of petrol or diesel fell to 83 on Thursday from 140 on Wednesday in the Loire-Atlantique department of western France, the government office there said.
French nuclear power capacity was cut by as much as five gigawatts due to stoppages. That is equivalent to just over six percent of the country's total production capacity.
Even if power industry experts say the nuclear plant strike was unlikely to provoke major blackouts due to legal limits on strike action and power imports from abroad, the action usually raises running costs for the EdF power utility.
With dockers striking at the southern port of Marseille, the number of ships waiting at sea to offload oil, gas and chemicals rose to 21 from what would normally be about five, the port authority said.
A protest over pension reform in 2010 died once police broke up pickets at supply depots and railworkers came under pressure by stoppages that hit their paycheck.
Oil giant Total S.A., said all but one of its fuel distribution depots were working. It warned, however, that two of its five refineries in France were at standstill and two more set to halt in coming days.
The CGT is waging a lonelier battle this time. Laurent Berger, head of the rival CFDT union and a backer of the planned labour reform, said: "The political and industrial relations climate has turned hysterical ... let's calm things down."
Additonal reporting by Andrew Callus, Bate Felix, Simon Carraud in Paris and correspondents around France; Writing by Brian Love; Editing by Tom Heneghan