As Greek workers took to the streets in protest on Thursday, Alexis Tsipras was for the first time on the other side of the divide. Unions -- a key support base for the prime minister’s Syriza party -- chanted in rallies held in Athens the same slogans Tsipras once used against opponents. Doctors and pharmacists joined port workers, civil servants and Athens metro staff in Greece’s first general strike since he took office in January, bringing the country to a standstill for 24 hours. As many as 20,000 protesters gathered in central Athens while a small group of anarchists at the tail of the demonstration threw petrol bombs at police officers at around 1:30 pm local time, a police spokesman said, requesting anonymity in line with policy. The police responded with tear gas and stun grenades. Greece’s biggest unions, ADEDY and GSEE, are holding marches accusing Tsipras of bowing to creditors and imposing measures that “perpetuate the dark ages for workers,” as the country’s statistical agency released data showing that 1.18 million Greeks, or 24.6 percent of the workforce, remained unemployed in August. The 41-year-old Greek premier, who was among anti-austerity protesters in previous general strikes, is now racing to complete negotiations with creditors on belt-tightening in exchange for the disbursement of 10 billion euros ($10.7 billion) to be injected into banks. Failure to reach an accord with euro-area member states and the International Monetary Fund on policies including primary residence foreclosures, and stricter rules on overdue taxes, would put the solvency of the country’s lenders in doubt. “The economic policies Tsipras has to implement are definitely harsher than warranted, and also harsher than they would be if it wasn’t for these seven months of brinkmanship and extreme political uncertainty,” said Manolis Galenianos, a Professor of Economics at the Royal Holloway, University of London. “This wasn’t necessary, it could have been avoided, and the government will now implement deeper cuts to achieve less ambitious fiscal targets.”