Riot police in Athens stormed a sit-in by striking metro workers Friday, a show of muscle from the government that critics said reeked of authoritarian rule and escalated tensions with unions angry over austerity cuts. The pre-dawn raid broke up the protest and hours later metro lines resumed service after workers were pressed back to work with requisition orders. \"The first trains have begun to operate and staff are returning to their posts,\" a development ministry source told AFP. \"For the time being the train frequency is low but the situation is returning to normal.\" The government had ordered a civil mobilisation on Thursday to force the Athens metro staff to halt their strike, which had disrupted traffic in the Greek capital for nine days. \"Under no circumstances can the government allow the country to be derailed,\" Development Minister Costis Hatzidakis said in a televised address. \"We are satisfied that the metro staff put the trains back into operation,\" Development Minister Costis Hatzidakis said in a televised address. \"Certainly passengers are even more satisfied,\" he said. Unions reacted by calling a general standstill in other forms of public transport on Friday and additional action has been scheduled for next week. Some 500 unionists rallied to a call for support at the metro depot, an AFP journalist said. And a leading member of Greece\'s largest union GSEE said a general strike would also be held in response. \"There are plans to bring forward a nationwide strike that was originally planned in February,\" George Gavrilis, a GSEE board member, told state television NET. Police on Friday handed out requisition forms to thousands of transport unionists. Under the emergency law evoked by authorities, strikers face arrest if they refuse to comply. A leftist party in the ruling coalition Thursday criticised the civil mobilisation, calling it \"an extreme option\". Opposition parties have also criticised the emergency measures as \"barbaric\" and \"authoritarian.\" \"This unconstitutional and coup d\'etat-style mobilisation should be repealed immediately,\" radical leftist party Syriza, which heads the opposition, said in a statement. Metro staff oppose government plans to reduce their pay in line with wages in the broader public sector, part of reforms tied to the country\'s massive EU-IMF loan bailout. Their protest comes as a test of the government\'s determination to implement the harsh austerity measures demanded by Greece\'s creditors in exchange for a massive bailout. Prime Minister Antonis Samaras said Thursday: \"The Greek people have sustained major sacrifices. I can allow no exceptions.\" \"Public transport does not belong to guilds. It belongs to the people,\" Samaras said. The government said strikers had also shown contempt for court rulings that had declared the metro strike illegal earlier this week. Government spokesman Simos Kedikoglou said the strike was hurting the Greek economy, adding in televised remarks: \"There have been court rulings on the issue and the law must be applied.\" The metro strike is estimated to have cost the Greek economy some 10 million euros ($13 million) according to reports. Transport workers had already scheduled work stoppages on January 29 and a 24-hour strike on January 31. Sailors have also called a two-day strike starting on January 31 and health workers will hold a work stoppage during that day.