French prime minister Manuel Valls has opened the door to possible changes in a labour bill that has sparked intensifying strikes and protests - but insisted the government will not abandon the measures.
The reforms, aimed at boosting hiring by loosening protection for workers, have sparked the toughest challenge yet to President Francois Hollande and his Socialist government as union activists disrupt fuel supplies, trains and nuclear plants.
"There could be improvements and modifications," Mr Valls said. He did not elaborate on what might be changed, and insisted that the "heart" of the bill should remain. Withdrawing the bill "is not possible", he said.
Members of the CGT union immediately dismissed the gesture, saying they want the bill scrapped, not modified.
"It's inadmissible," said Arnaud Pacot of the CGT in the Aube region of eastern France, from a nuclear plant being blocked by protesters.
Union activists blocked a major bridge across the Seine River on France's northern coast and a tunnel in Marseille as part of protest action and one-day strikes around the country.
Demonstrators gathered early at a central square in the port town of Harfleur, setting off fireworks and air horns. Activists were unapologetic about the disruption they planned.
"We have to hit where it hurts," said union official Gilles Guyomard. "And where it hurts is the bosses' wallets."
The activists then went to the 2km Normandy Bridge at Le Havre, setting a pile of tyres on fire and blocking toll booths. Protesters dispersed two hours later after closures that jammed traffic and stranded motorists.
Mr Valls insists the bill is "good for workers" and small businesses, and argued that many of its critics are ill-informed of its contents.
The bill loosens the 35-hour working week, makes it easier to fire workers in times of economic downturn, and weakens the power of unions to set working conditions across an entire sector.
France's junior minister for transport later insisted that strikes at oil refineries and nuclear plants will not leave the country without fuel or electricity.
Alain Vidalies said on Europe-1 radio: "We don't risk running out."
He acknowledged "the situation remains tense", with five of the country's eight oil refineries on strike and one closed for maintenance.
After days of fuel shortages, he said supplies to petrol pumps improved slightly on Thursday. He said: "We unblocked 11 (fuel) depots and will continue to unblock them."
He played down any concerns that nuclear plant strikes would lead to blackouts, saying France could import electricity if needed.