France braced for even worse transportation woes when the new work week begins Monday due to nationwide strikes over the government's redesign of the national retirement system. French President Emmanuel Macron convened top officials to strategize for the high-stakes week ahead.

Sunday saw more travel chaos as the strikes entered their fourth day, with most French trains at a standstill. Fourteen of Paris' subway lines were closed, with only two lines — using automated trains with no drivers — functioning. International train routes also suffered disruptions.

Monday will be an even bigger test of the strike movement's strength and of commuters' and tourists' patience. Unions are calling for more people to join the strike Monday. Many employees worked from home or took a day off when the strikes began last week, but that's not sustainable if the strikes drag on.

Warning of safety risks, the SNCF national train network and the Paris transit authority RATP warned travelers to stay away from train stations Monday instead of packing platforms for the few trains still running.

"On Dec. 9, stay home or find another means of locomotion," SNCF warned travelers.

Facing a challenging week ahead, French Prime Minister Edouard Philippe met Sunday afternoon and evening with government ministers involved in the pension reform, and later met with Macron.

Macron, a centrist former investment banker, argues that the retirement overhaul will make a convoluted, out-dated pension system more fair and financially sustainable, uniting 42 different plans into one. The government says it won't change the official retirement age of 62, but the new plan is expected to include financial conditions to encourage people to work longer as lifespans lengthen.

Unions see the reforms as an attack on worker rights and fear that people will have to work longer for smaller pensions. Some French workers can now retire in their 50s.

The new retirement plan will affect all French workers but the strikes involve primarily public sector workers, including train drivers, teachers and hospital employees.

New nationwide protests are scheduled Tuesday and the prime minister will release details of the new retirement plan on Wednesday.

Yellow vest activists joined the protests Saturday, adding retirement reform to their list of economic grievances in protests around the country.

A few thousand yellow vest protesters marched from the Finance Ministry complex on the Seine River through southeast Paris, pushing their year-old demands for economic fairness — and adding the retirement reform to their list of grievances. Most marchers were peaceful but some threw projectiles or pushed riot officers, prompting repeated bursts of tear gas from police.

The marchers appear to be emboldened by the biggest national demonstrations in years Thursday that kicked off a mass strike-and-protest movement against President Emmanuel Macron's redesign of the pension system.

Truckers striking over a fuel tax hike disrupted traffic on highways from Provence in the southeast to Normandy in the northwest. A similar fuel tax is what unleashed the yellow vest movement a year ago, and this convergence of grievances could pose a major new threat to Macron's presidency.

Macron says the reform, which will streamline a convoluted system of 42 special pension plans, will make the national pension system more fair and financially sustainable. The government says it won't raise the official retirement age of 62 but the plan is expected to including financial conditions to encourage people to work longer. Those most against the changes are workers in special categories like transport who can now retire earlier than 62.

So far the travel chaos is not deterring the government. Prime Minister Edouard Philippe plainly told the French in a nationwide address Friday: "You're going to have to work longer."

He will present details of the plan next week. Philippe did offer one olive branch, saying the changes would be progressive so that they don't become "brutal."

Unions, however, see the plan as a threat to workers' rights and are digging in for a protracted strike. They also plan new nationwide retirement protests Tuesday.

Emmanuel Buquet, an unemployed 51-year-old from Rouen, said the mass protests gave a new impetus to the waning yellow vest movement.

"Yellow vests are back out in the streets," he told the AP. "It's getting worse and worse. We've obtained nothing since last year, just crumbs. The reforms are getting stronger and stronger."

In a society accustomed to strikes, many people have supported the protests, although that sentiment is likely to fade if the French transport shutdown continues through next week.

"I knew it was going to last ... but I did not expect it to be that chaotic," Ley Basaki, who lives in the Paris suburb of Villemomble and commutes to work in the capital, told The Associated Press on Saturday at the Gare de l'Est train station. "There is absolutely nothing here, nothing, nothing. There is no bus, nothing."

Many travelers were using technology and social networks to find ways around the transport strike — working from home, using ride-sharing apps and riding shared bikes or electric scooters.

But some were using technology to support the strike. A group of activist gamers was raising money via a marathon session on the game-streaming site Twitch. Their manifesto says: "In the face of powers-that-be who are hardening their line and the economic insecurity that is intensifying," they are trying to "occupy other spaces for mobilization and invent other ways of joining the movement."