Turkish police clashed with anti-government protestors into the early hours of Monday, activists said, ahead of planned demonstrations by unions.

Police used tear gas and water cannon against demonstrators in Ankara, and blocked thousands of activists in Istanbul from reaching the city’s Taksim Square, after their camp there was cleared by security forces, injuring hundreds.

Clashes occurred in several parts of Istanbul, with opposition activists saying police fired water cannon at a hospital near Taksim Square where demonstrators had taken refuge.

The activists also said online that some of them had been attacked by government supporters wielding clubs and knives, and that the police had not intervened.

Local media reported that a mob shouting pro-government slogans attacked an office of the opposition Republican People’s Party in Istanbul.

Five Turkish unions said they would hold demonstrations on Monday to protest the police violence around Saturday’s clearance of the park camp, Hurriyet Daily News reported online.

The Taksim Solidarity activists’ group said there was an excessive use of rubber bullets, tear gas and stun grenades, noting that women, children and elderly people were present.

Istanbul Governor Huseyin Avni Mutlu warned people not to attempt another gathering in the square.

“I ask the people: do not come to Taksim,” he was quoted as saying by Hurriyet late Sunday. “We will not allow any gathering in Taksim under the current circumstances. We are taking all kinds of security measures in this respect.” More than 350 people have been arrested since the two-week-old camp on Taksim Square was cleared on Saturday, most of them on Sunday, the Istanbul Bar Association was quoted as saying by Hurriyet.

The initial protests were against a planned building project in the park, but have sparked wider demonstrations against what activists call the increasingly authoritarian rule by Prime Minister Recep Tayyip Erdogan’s administration.

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