Greek trade unions’ 24-hour strike against pension reforms brought the country to a standstill Thursday. The general strike disrupted public transport leading to cancelation of flights and ferries, and closed down schools, courts and pharmacies, and left public hospitals with only emergency staff.

The one-day strike has been called to protest the pension reforms that are part of Greece’s third international bailout. The left-led government is trying to refurbish the pension system by increasing social security contributions to avoid pension cuts. However, experts reportedly say that these reforms will cause majority of the people to lose two-thirds of their income to contributions and taxes.

More than 20,000 supporters of a Communist party-backed union were marching through central Athens, and around 10,000 more people, including lawyers, were gathering for a separate demonstration, the Associated Press (AP) reported.

Heavy police presence was seen in Athens in the wake of the demonstrations. A hotel in central Athens, where Greece’s international debt inspectors were staying, was guarded by police, according to the AP. Thousands of workers, self-employed professionals, farmers and pensioners gathered in central Athens for protests, according to Reuters.

"We cannot live, we cannot survive with what the government is asking from us," farmer Socratis Aleiftiras told Reuters. The pension reform requires the workers to pay threefold for social security contributions in coming years.

Limited transport was provided in the capital for a few hours in the day and over a dozen domestic flights were canceled, the AP reported. Farmers reportedly blocked highways, state-run hospitals operated on emergency staff, while state schools were shut.

The strike, according to the AP, is the most significant against the government of Prime Minister Alexis Tsipras since he assumed power in September 2015. The protests come at a time when the government is negotiating with the country’s debt inspectors, who arrived in Athens this week to examine progress on Greece’s bailout obligations.