A national strike over a government savings plan grounded flights and disrupted public transport in Belgium on Tuesday, with tens of thousands expected to join a demonstration in Brussels.

Axar.az informs, citing France 24, Brussels airport – Belgium’s largest – cancelled all departures as security workers downed their tools. Charleroi Airport, a major European hub for low-cost airline Ryanair, said it could not operate any flights due to lack of staff.

The strike is the last in a series to hit the European country since Flemish nationalist Bart De Wever took office as prime minister in February.

Grappling with a budget deficit whose size violates European Union rules, the government is looking to reform pensions and make other savings that have infuriated trade unions.

“This government promised more sustainable jobs and increased purchasing power. Hot air! And once again, everyone is paying, except the rich,” trade union CSC said, calling on people to take to the streets in protest.

Unions expect tens of thousands to join a rally in Brussels on Wednesday, as delays and cancellations also hit the capital’s metro, tram, and bus services.

Police in the capital advised citizens to avoid some central areas and travel by car.

The protest action will increase pressure on De Wever’s coalition government, which on Monday failed to agree on a budget, forcing the prime minister to postpone a key speech to parliament scheduled for Tuesday.

Trade unions have mounted strong opposition against planned reforms including cutting early retirement and a wage indexation freeze.

As it looks to find about 10 billion euros ($12 billion) in savings, Brussels – long a laggard – has also pledged to ramp up spending on defense as part of a NATO push to boost rearmament.

De Wever came to power after lengthy coalition talks following Belgium’s federal elections in June last year.