Protests and strikes against unpopular pension reforms kicked off again Tuesday across France, with police security ramped up amid government warnings that radical demonstrators intended “to destroy, to injure and to kill”.

Concerns that violence could mar the demonstrations prompted what Interior Minister Gérald Darmanin described as an unprecedented deployment of 13,000 officers, nearly half of them concentrated in the French capital.

After months of upheaval, an exit from the firestorm of protest triggered by President Emmanuel Macron’s changes to France’s retirement system looked as far away as ever. Despite fresh union pleas that the government pause its hotly contested push to raise France’s legal retirement age from 62 to 64, Macron seemingly remained wedded to it.

The French leader previously used a special constitutional power to ram the reform past legislators without allowing them a vote. His move this month further galvanised the protest movement. Violence has since flared and thousands of tonnes of stinking garbage have piled up on Paris’s streets as sanitation workers strike.

The wave of protests Tuesday marked the 10th time since January that unions have called on workers to walk out and for demonstrators to flood the nation’s streets to object to Macron’s retirement changes, which are a key priority of his second term as president.

Demonstrations got under way peacefully Tuesday morning, with large crowds in multiple cities. But police braced for violence later in the day. The interior minister said more than 1,000 “radical” troublemakers, some from overseas, could latch on to marches in Paris and elsewhere.