The leader of France's hardline CGT union on Wednesday urged all workers to join pension strikes that have crippled public transport over the past month, as a showdown with President Emmanuel Macron enters a second month.
In his New Year's address Tuesday Macron vowed not to back down on his plan to replace France's 42 separate pension schemes with a single system that would require people to work longer.
The government says the changes are necessary to make the system fairer for all and more sustainable but unions argue that workers, particularly in the public sector, will lose out.
Reacting to Macron's speech, CGT leader Philippe Martinez called for strikes "everywhere" from next week, both "in the public and the private sector".
"Faced with a self-satisfied president who thinks that everything is going fine in this country we have to send a stronger warning sign," he told BFM news channel.
"We're calling on all the French to mobilize, attend demonstrations and go on strike," he added.
The 28-day strike, which left thousands of travellers stranded over the Christmas holidays, is on course to exceed the longest transport strike to date in France, which lasted for 28 days in 1986 and early 1987.
Macron's New Year's address was closely watched for signs that the government's resolve might be weakening.
But while calling for a "rapid compromise" during a new round of negotiations with unions next week, Macron vowed that the reforms "will be carried out."
Reacting to his comments, Yves Veyrier, secretary-general of the Force Ouvriere (FO) Union, one of France's biggest, said: "I don't get the impression that there is much room for negotiation."
Far-left leader Jean-Luc Melenchon, head of the France Unbowed (LFI) party, added on Twitter: "These are not (New Year) wishes but a declaration of war to the millions of French who refuse his reform."
Already another day of mass protests is set for January 9, when teachers, dockers, hospital workers and other public sector employees are expected to join transport workers by striking for the day.
Energy workers have also called for a three-day blockade of the country's oil refineries and fuel depots starting January 7, raising the spectre of petrol shortages.
But the strike participation rate is waning, with just 7.7 percent of employees at train operator SNCF on strike Tuesday, far below the levels seen when the protest began on December 5.
On Tuesday, musicians from the Paris Opera, whose employees enjoy a special retirement regime dating back to 1698, played a protest concert outside the Bastille Opera for several hundred passers-by.