Protesters throw red paint as they clash with riot police during a 24-hour general strike in central Athens, Greece, on May 30, 2018. Greece was gripped on Wednesday by a 24-hour nationwide general strike called by trade unions to protest ongoing austerity. (Xinhua/Marios Lolos)

ATHENS, May 30 (Xinhua) -- Greece on Wednesday was gripped by a 24-hour nationwide general strike called by trade unions to protest ongoing austerity.

The debt-laden country is set to exit the third bailout program this summer after eight years. However, under commitments undertaken in the context of the aid mechanism, Greece will remain under surveillance and will have to implement more difficult measures, such as fresh cuts on pensions from 2019.

"We join forces against austerity, unemployment, over taxation" was the main slogan of the new industrial action called by the umbrella trade federations of the public and private sectors, ADEDY and GSEE on Wednesday.

As thousands of strikers were marching in central Athens, public services were closed, hospitals run on skeleton staff and public transport was also disrupted.

Dozens of domestic and international flights were cancelled or rescheduled as air traffic controllers participated in the mobilization with a three-hour work stoppage.

Ships remained moored at ports, railway services were also disrupted, while buses run on reduced shifts.

Demonstrators protested in front of the parliament against the next round of cuts in pensions and tax hikes, pledging to continue protesting until their demands are satisfied.

Greek labor unions have organized dozens of general strikes and thousands of rallies since 2009, but Greek governments and international creditors have insisted that there was no other way than painful sacrifices to keep the Greek economy afloat and in the euro zone.

"There are no illusions. This attack (with harsh measures) against people will go on. The workers' movement should get prepared for more struggle," the general secretary of the Greek Communist party Dimitris Koutsoumbas said during the protest.

"Over the past nine years they have brought suffering to the Greek people. They shrink wages, pensions, social rights, the standards of public health and social security services," Michalis Yannakos, president of the Panhellenic Federation of Employees in Public Hospitals, told Xinhua during the rally.

"If the post-bailout era will be like this, with such measures, unfortunately, we are sorry, but we cannot accept it," he said.