PARIS (AP) - Bolstered French police forces clashed with demonstrators in numerous cities Tuesday as hundred of thousands of marchers protested President Emmanuel Macron's unpopular retirement reform.

Security was ramped up for the 10th round of protest marches since January after the government warned that some demonstrators intended “to destroy, to injure and to kill.”

The Interior Ministry put the number of demonstrators nationwide at 740,000, down from more than 1 million five days ago when protesters voiced their rage at Macron's order to ram the bill raising France's legal retirement age from 62 to 64 through parliament without a vote. The Paris police counted 93,000 in Paris compared with 119,000 last Thursday, when violence reached a peak.

In a bid to keep up pressure on the government to simply withdraw its retirement measure, unions organizing the protests called for new strikes and marches on April 6.

In a sign that protests may be losing a little steam, sanitation workers in Paris announced that they are suspending their more than three-week-long strike that has left piles of stinking garbage uncollected on the capital's streets. Growing piles of rotting garbage in the French capital became a symbol of the larger protests.

The CGT union, which organized the strikes, said in a statement that workers will return to their jobs Wednesday. It was unclear whether private companies responsible for keeping some Paris districts clean will return to work.

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

A group of security forces in Paris at one point withdrew behind the wooden doors of a residential building during hours-long standoffs against ultra-leftist militants attacking with various projectiles and fireworks. A fire raged outside the door.

After months of upheaval, an exit from the firestorm of protest triggered by 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, Macron seemingly remained wedded to it.

His order to use a special constitutional power to ram the reform past legislators without allowing them a vote galvanized the protest movement.

The Eiffel Tower's website announced that strikers had closed down the world-famous tourist attraction. The Louvre Museum was similarly strike-bound Monday.

“I'm protesting because this reform is deeply unfair to workers, women, and young people,” said Camille Sabatier, 19, a political science student at the Sorbonne.

“It's no longer acceptable that a powerful man could force such a bill without a vote by parliament,” she said.

“Everybody is getting madder,” said Clement Saild, a train passenger at Paris' Gare de Lyon railway station, where tracks were temporarily invaded and blocked Tuesday by protesting workers. He said he supports the strikes despite their impact on transportation and other services.

“I am 26, and I wonder if I will ever retire,” he said.

Macron's argues that France's pension system will dive into deficit without reform, because of the lower birth rates and longer life expectancy in many richer nations. Macron's opponents say additional funding for pensions could come from other sources, without having to make workers retire later.

Demonstrations got underway peacefully Tuesday morning, with large crowds in multiple cities. But tensions rose as marches concluded in Paris, Lyon, Nantes, Bordeaux and elsewhere.

Police were hit with objects and responded with tear gas to disperse demonstrators in the western city of Nantes. In the center of Lyon, in the southeast, there were numerous confrontations between demonstrators and police as the protest wound down.

The interior minister had said more than 1,000 “radical” troublemakers, some from overseas, could latch on to marches in Paris and other cities.

“They come to destroy, to injure and to kill police officers and gendarmes. Their goals have nothing to do with the pension reform. Their goals are to destabilize our republican institutions and bring blood and fire down on France,” the minister said Monday.

Some protesters, human rights campaigners and Macron's political opponents allege that police officers have used excessive force against demonstrators. A police oversight body is investigating multiple claims of wrongdoing by officers.

The striking railway workers outside Gare de Lyon marched behind a banner that alleged: “The police mutilates. We don't forgive!”

Lucie Henry, a 36-year-old protester, said that by skirting parliament to impose his reform, Macron “has set everyone on fire.”

“What adds fuel to the fire is the behavior of the government, the police violence in particular,” she said.

Macron's opponents are urging him to cool tempers by backing down. Union leader Laurent Berger appealed Tuesday for a pause in implementing the retirement reform and for mediation.

“If we want to avoid tensions - and I want to avoid them -- what the trade unions are proposing is a gesture to calm things down,” he said. “It must be seized.”

Prime Minister Elisabeth Borne reportedly offered to receive the eight unions organizing the protests. Berger, head of the moderate CFDT, said he agreed, French media reported. It was not clear whether other unions backed that stance.

The latest round of protests prompted Macron to indefinitely postpone a planned state visit this week by King Charles III.

Government spokesman Olivier Veran insisted, however, that France remains a welcoming place for all non-royal visitors.

“Life goes on,” he said.

Elaine Ganley, Jade le Deley, Jeffrey Schaeffer, Helena Alves and Masha Macpherson contributed to this report.