For the second time in 16 days, millions of people took to the streets of cities throughout France on Thursday, trade unions said, to protest President Nicolas Sarkozy's pension reform. In addition, nationwide strikes disrupted public transport and hampered many other state services, such as schools and postal deliveries, according to dpa. At the heart of the reform, which has already passed the National Assembly, is the gradual increase of the retirement age from 60 to 62 by 2018. According to the powerful CGT trade union, some 2.9 million people took part in demonstrations in more than 230 cities. However, the interior ministry estimated the number of protesters at about 1 million. Union leaders had hoped to mobilize at least as many protesters as in the last nationwide protest against the reform on September 7, when they said more than 2.5 million people demonstrated. Railway workers opened the nationwide strikes by walking off their jobs late Wednesday. The national rail network SNCF said half of its scheduled high-speed TGV trains and only about one in four regional trains operated Thursday. In addition, public transportation was disrupted to varying degrees in Paris and nearly 80 other cities. The French civil aviation agency DGAC said that half of all scheduled flights were scrubbed at Paris' Orly Airport, with 40 per cent cancelled at the capital's other major airport, Charles de Gaulle, and other French airports. In addition, unions said that about half of all public school teachers took part in the job action. However, both Sarkozy and Labour Minister Eric Woerth have said they would not back down on the plan to increase the age of retirement. As a result, union leaders were to meet Friday to discuss a continuation of the protest movement, with a general strike or a job action of more than one day's duration among their options.