French President Francois Hollande threatened to ban demonstrations Wednesday, the day after protests erupted in Paris over labor reforms that the government has vowed to push through regardless of strong opposition.
"At a time when France is hosting the Euro (soccer tournament), when it is faced with terrorism, demonstrations can no longer be authorized if property and people and public property cannot be safeguarded," Hollande's spokesman Stephane Le Foll told a Cabinet meeting.
The comments sparked the ire of the left flank of his Socialist Party.
"There's a much simpler way than banning demos," said backbencher Benoit Hamon. "That is to reopen negotiations, wanted by three in four French people."
Earlier, Prime Minister Manuel Valls vowed to stand firm on the reforms despite mass protests against them.
"The government will not change a text which is already the outcome of a compromise sealed several months ago with reform-minded unions," Valls told France Inter radio.
Hollande's Socialist government is trying to push through a set of reforms to the labor market that will facilitate the procedure for dismissals, among other provisions, despite France's stubbornly high unemployment rate.
Critics see the reforms as skewed towards business interests, and strikes and clashes have flared since early March.
Amnesty International France also condemned the suggestion that the "fundamental freedom" to protest could be curtailed, calling for an independent inquiry into violent flare-ups at recent demonstrations.
On Tuesday, protesters and police violently clashed in Paris, with 40 people injured. Police and organizers gave wildly different figures for the turnout, with unions saying 1.3 million people had turned out across France while police estimated the crowds at 125,000 or more, some 80,000 of them in Paris.
Two further protest days are set for later this month.
The threat of force against social movements comes as the government set up stringent security measures in the wake of last year's terror attacks in the capital, mustering up to 90,000 police and private guards to provide security for the tournament.