Greek police have fired tear gas and charged at workers who had occupied the Acropolis in Athens in a protest over unpaid wages and lay-offs.
TV images showed police chasing the culture ministry workers around the ancient monument.
Dozens of workers had shut down the Acropolis on Wednesday morning, demanding two years of back pay.
They had barricaded themselves inside, padlocked the entrance gates and refused to allow in tourists.
The protesters said they intended to blockade the Acropolis, Greece's most famous tourist attraction, until 31 October. They have vowed to return to the site on Friday.
Greece has seen waves of strikes and protests over austerity measures agreed by the government to in order to secure a huge bail-out from eurozone countries.
As well as the back-pay issue, the workers are angry that about 320 temporary staff will lose their jobs when their contracts expire at the end of the month. They want the staff to be given permanent contracts.
"All our colleagues stand beside us, so the monument will not operate today no matter what happens," Nikos Hasomeris, one of the leaders of the striking workers, told Greek television earlier.
"We want the ministry to cancel the planned dismissal of 320 staffers and settle its dues to people who have been unpaid for 22 months."
But police in riot gear arrived on Thursday morning after a court order said the protesters were hindering access to an ancient site.
TV footage showed the police entering the site using a side entrance.
They used tear gas to clear protesters and a group of journalists who had gathered at the main gate. At least one person was arrested.
Speaking after the operation, Mr Hasomeris said the protests would continue.
"The authorities must accept their responsibilities," he said. He also accused the authorities of damaging the archaeological site.
Deputy Culture Minister Telemachos Hytiris offered to talk to the protesters but said he could not promise them permanent contracts.
"Thousands of short-term workers have been laid off until now, the law applies to all," he told Flash Radio in comments reported by the Associated Press news agency.
AP reported that dozens of bemused tourists hoping to visit ancient site watched the police operation unfold, some of them taking pictures of the officers.
"We know the workers have a right to protest, but it is not fair that people who come from all over the world to see the Acropolis should be prevented from getting in," said Spanish tourist Ainhoa Garcia.
The BBC's Malcolm Brabant in Athens said unpaid wages were a common cause for complaint in Athens, where the government is making progress in trying to cut its public deficit by not paying its bills.
Under Greek law a civil service job is guaranteed for life, our correspondents added, and there were few prospects for finding alternative work in the current crisis.
Latest figures show unemployment in Greece is at 12%, with those aged under 24 are worst affected.