France’s most serious nationwide work stoppage in decades frustrated weekend travelers Saturday as truckers blocked thoroughfares and vital transportation services continued to operate far below normal capacity.

Concern that President Emmanuel Macron’s proposed pension overhaul would force millions of people to work longer or face less lucrative benefits triggered the union-led strike on Thursday, bringing much of the country to a halt.

Truckers blocked roads Saturday in about 10 regions in France to protest a proposed tax hike on diesel fuel for commercial vehicles.

Yellow vest protesters, who have taken to the streets on Saturdays over the past year to voice frustration over the high cost of living in France, sought to capitalize on the nationwide strike.

Several hundred of them launched a new protest Saturday in Paris and they scuffled with police in the city’s Left Bank district.

Travel in France remained problematic Saturday, with only one in 10 regional trains running and one out of six high-speed TGV trains operating.

Air travel was returning closer to normal after authorities dropped travel restrictions.

More than 800,000 people participated in the first day of demonstrations on Thursday.

In response to what they see as an attack on hard-won worker rights, union leaders have promised to continue protesting unless Macron abandons the proposed pension overhaul, which officials admit would force employees to gradually work longer.

Unions have also announced another strike on Tuesday (Dec. 10).

Officials have given few details about the pension plan, but Macron’s office said Thursday that Prime Minister Edouard Philippe would unveil the framework next week after negotiations with unions.

The strike is a test of the political prowess of Macron, a former investment banker who won the presidency on the promise to transform France.

Macron wants to standardize and simplify the country’s retirement system comprised of 42 pension plans, maintaining it is not financially sustainable or fair.

Many workers, particularly teachers, worry Macron’s reform will leave them with less retirement money.

With workers living much longer and a large segment of working-age citizens unemployed, analyst Jean Peteaux of Sciences-Po Bordeaux University said France’s pension system is under significant financial pressure.

Peteaux also said it is uncertain if the government’s method to address the issue will succeed.