Paris: French commuters faced travel chaos on Thursday after transport workers went on strike over plans to scrap their pension privileges, handing President Nicolas Sarkozy a first major challenge of his reforms.

Unions called the 24-hour strike from late on Wednesday in an attempt to force concessions from the government, which plans to scrap privileges that allow a minority of public sector workers to retire earlier than their peers.

The SNCF state rail network said only a fraction of trains would run, while bus and tram services faced disruption in 27 major cities over the pensions row, and a law forcing transport staff to provide a minimum service during strikes from January.

"Traffic will be very reduced today with less than five percent of trains running compared with a normal day," Guillaume Pepy, the SNCF's executive director general, said in an
interview in Thursday's Le Parisien newspaper.

Rail stations normally packed with early morning commuters were almost deserted apart from a few stranded passengers.

"It's crazy," said Kwame Boakye, who was trying to get home to Zurich with his family from the Gare de l'Est in Paris.

"Yesterday they told me the train is leaving at 0824. Now they just told me there's no train. What am I going to do with the children now?"

Radio stations reported heavy traffic on the roads coming into Paris and the "Vel'lib" city bikes newly introduced by the city hall were heavily in demand.

The Paris transport authority RATP said a reduced service was operating on most metro lines, but fewer than one in 10 buses were running.

Gas and power utility staff, who would also be subject to the new pension rules, were due to walk off the job too, although cuts in supplies were not expected.

Airlines could also be affected if air traffic controllers were unable to get to work, the authorities said, though most cross-Channel Eurostar trains were due to run as usual.