London and Paris CNN Business  — 

Only about half the trains on regional and intercity lines were running Tuesday in France and Eurostar canceled some services between London and Paris, as a strike by energy workers spilled over into other sectors of the economy.

One in two trains were canceled on some suburban rail lines in Paris and Eurostar canceled four services between the French and British capitals on Tuesday and Wednesday, blaming strike action.

French unions called for a nationwide strike on Tuesday, expanding a weeks-long refineries strike that has caused fuel shortages and miles-long lines at gas stations. Workers, who now also include teachers, are asking for higher salaries amid rising living costs.

According to France’s education ministry, nearly 10% of high school teachers were on strike Tuesday. French nuclear giant EDF said that just over 16% of its workers were on strike as of midday Tuesday, which could delay maintenance work on reactors.

Alongside wage demands, workers are defending their right to strike, angered by the government’s decision to force some refineries employees to work in order to restore fuel supply. Nearly one in three gas stations nationally are still without at least one type of fuel.

The government’s decision to threaten some refineries workers with fines and criminal charges if they refused to work has been a key driver of wider strike action, as workers deem the move a threat to their constitutional right to protest.

Interior Minister Gerald Darmanin told French radio station RTL on Tuesday that he had ordered police “to obviously leave Frenchmen and women who wish to protest in constitutional conditions and to respect this constitutional right.”

But the government is likely to continue to issue work orders today to resolve fuel supply issues, according to government spokesperson Olivier Veran. “There will be as many ordered back to work as necessary,” to respond to the needs of French people, Veran told France 2 television.

He criticized ongoing blockades at refineries by French union CGT, given that a majority of workers had now agreed to wage deals with ExxonMobil and TotalEnergies. “To continue to block the means of work for everyone, to stop people from accessing this means of work, is not a normal situation,” Veran added.

CGT has demanded a 10% pay rise, more than the 7% increase agreed between TotalEnergies and two other unions, CFE-CGC and CFDT. While ExxonMobil workers agreed to end their blockade of the Fos-sur-Mer refinery and depot in southern France late last week following salary negotiations, strikes continue at TotalEnergies refineries.

The dispute over pay takes place against a backdrop of rising living costs in France, where electricity bills are surging as a result of a cut in Russian natural gas supplies that has sparked an energy crisis in Europe. On Sunday, tens of thousands of people took to the streets of Paris to protest the cost-of-living crisis and what they said was climate inaction by the French government.

-— Marguerite Lacroix and Natacha Bracken in Paris contributed reporting.