At least 1.1 million people protested on the streets of Paris and other French cities Thursday amid nationwide strikes against plans to raise the retirement age. The events affected travel across the country and closed tourist attractions in Paris, with fears that the disruptions will continue.

Emboldened by the high turnout, French unions announced new strikes and protests Jan. 31, vowing to try to get the government to back down on plans to raise the standard retirement age from 62 to 64.

More than 200 rallies were staged around France on Thursday, including a large one in Paris involving all France’s major unions.

The Interior Ministry said more than 1.1 million people protested across France, including 80,000 in Paris. Unions claimed more than 2 million people took part nationwide, and 400,000 in Paris.

Riot police pushed back against some protesters throwing projectiles on the sidelines of the largely peaceful Paris march. Some other minor incidents briefly flared up, leading officers to use tear gas. Paris police said that 38 people had been detained.

Meanwhile, strikes across France severely disrupted transport and other public services.

Most train services around France were cancelled, including some international connections, according to the SNCF rail authority. About 20% of flights out of Paris’s Orly Airport were cancelled and airlines warned of delays.

The strike also affected some monuments. The Versailles Palace was closed Thursday while the Eiffel Tower warned about potential disruptions and the Louvre Museum said some exhibition rooms would remain closed.