About 1,500 petrol stations in France have run dry or are about to close as fuel supplies are hit by strikes over government pension reforms, officials say. A blockade of oil refineries has lasted a week and the body that supplies most supermarkets says one in four petrol stations is affected. President Nicolas Sarkozy has called a crisis cabinet to protect supplies. He told reporters that the reforms were "essential" and would be carried out. The exact number of France's 12,000 petrol stations affected by the strikes is unclear, but oil company Exxon Mobil has described the situation as "critical". A spokeswoman said that anyone looking for diesel around Paris or in the western area of Nantes would face problems. Severe shortages have been reported in Brittany in north-west France and the International Energy Agency says that France has begun tapping into its emergency oil reserves. Workers at France's 12 oil refineries have been on strike for a week and entrances to many of the country's fuel distribution depots have been blocked. Panic-buying was blamed for a 50% increase in fuel sales last week. The head of the Leclerc chain of supermarkets, Michel Edouard Leclerc, warned that at the current rate his company's petrol stations would be empty within two to three days if the blockade of refineries remained and fuel imports were paralysed. Go-slow Strike action against the government's reform plans is being ramped up, with lorry drivers starting the week by staging a go-slow on motorways around several major cities including Paris, Lille and Lyon. A further day of strikes is scheduled for Tuesday, on the eve of a key Senate vote on the pensions bill. Half of all flights to and from Paris's Orly airport and one in three flights at other airports are being cancelled, according to aviation officials. Airport operator ADP said there were already some delays at the capital's largest airport, Charles De Gaulle, on Monday because of strikes by oil workers. Street protests have been planned in a number of cities and disruption is also expected on public transport and in schools. The government wants to raise the retirement age from 60 to 62 and the full state pension age from 65 to 67. Burning cars There were already demonstrations outside 261 schools on Monday, which the education ministry said had been blockaded. In the western suburb of Nanterre in Paris, dozens of students clashed with riot police who fired rubber bullets. Shop windows were reported broken in the Saint-Denis suburb, where education officials said more than half the areas secondary schools had been blockaded. In Lyon, several cars were burned and one teacher whose car was badly damaged by fire complained: "They want to fight [against the pension reform]. OK, but they have to understand the meaning of what they are doing". Credit: BBC