rench workers will step up their protests against pension reforms next week, a top trade union leader says.
Bernard Thibault, head of the CGT workers' confederation, made the statement as union leaders prepared to discuss plans to hold a seventh day of national protests across France.
Meanwhile, rolling strikes are continuing against government plans to raise the pension age from 60 to 62.
Blockades of refineries and fuel depots have led to fuel shortages.
The pension reforms bill is set to be speeded up to make sure it it is voted on on Friday, a parliamentary source has told Reuters news agency.
The lower house has already approved the bill, which aims to raise the retirement age from 60 to 62 and the full state pension age from 65 to 67. On its website, the Senate says it will extend the debate on pension reform into Saturday and Sunday if necessary.
On Wednesday, it adopted an amendment calling for a full review in 2013 of pension reforms.
Unions are meeting late on Thursday to decide whether to call a seventh national day of protest, possibly on Tuesday 26 October.
However, union leaders fear they may lose momentum because of the national holiday of All Saints' Day at the end of next week, when the schools and many salaried workers will be away.
President Sarkozy has called for an end to the disruption.
"We cannot be the only country in the world where, when there is a reform, a minority wants to block everyone else," he said on Thursday.
"By taking hostage the economy, companies and the daily lives of French people, we are going to destroy jobs."
Stepping up action Mr Thibault told RMC radio on Thursday: "The government remains intransigent. We need to continue with massive action as soon as next week... We will ask the unions for strong action that will allow people to stop work and go on to the streets."
In the southern port city of Marseille, there is no public transport, trains have been delayed or cancelled and the ports blockaded. The rubbish collectors' strike, now in its 10th day, and the nine-day rubbish collectors' strike means several thousand tonnes of refuse is piling up on the city's streets.
The top central government official in the area, Michel Sappin, said: "There is a real danger to the safety and health of Marseille."
The unions' tactics are clear, says the BBC's Matthew Price in the city - to cause discomfort, if not chaos, and to create uncertainty across the country. They believe that keeps the pressure on the government to change its retirement plans but, adds our correspondent, it also risks alienating the public, who so far according to surveys still support the strikers.
The strikes are hitting the entertainment industry, too. Singer Lady Gaga has postponed two concerts in Paris on Friday and Saturday.
A statement on her website says this is because "there is no certainty that the trucks can make it" to the venue.
Thousands of students marched in Paris, Marseille, Toulouse and Bordeaux.
In Bordeaux, demonstrators carried banners reading, "We would have burnt this reform but there's no petrol left", the AFP news agency reported.
In Lyon, youths clashed again with riot police, throwing bottles and overturning a car. Police retaliated with tear gas.
The protests have largely been peaceful with the exception of Lyon and the Paris suburb of Nanterre.
Across France, a number of universities are blocked or disrupted.
Electricity imports Ahead of the vote, correspondents say unions are stepping up the pressure on a 10th day of refinery strikes, go-slows on motorways and work stoppages at regional airports.
The BBC's Christian Fraser in Paris says there is a precedent for such a move.
In 2006, student protests forced the government to retreat on the controversial youth labour scheme, even after then President Jacques Chirac had signed it into law. Some unions want to continue the protests whatever happens in parliament, but that will depend on public support and the resolve of their members, many of whom have gone without pay for days even weeks, our correspondent adds.
About a quarter of France's service stations had no fuel on Wednesday, and strikes also stopped work at two of France's three liquefied natural gas (LNG) terminals.
On Wednesday, the country began importing electricity as the wave of protest action took hold of energy supplies.
At least 12 of France's 58 reactors were shut for maintenance, but the unions say production has been cut at four others.
As well as the general strikes and protests, there have been six days of co-ordinated action in the past six weeks that have brought as many as three million people to the streets.
