Thousands of protesters marched to Istanbul’s Taksim Square on Saturday chanting slogans against the government and police after security forces killed a Kurdish demonstrator in south-east Turkey.

The protest had been planned as part of larger unrelated anti-government demonstrations that have swept through the country since the end of May, but became a voice of solidarity with the Kurds after Friday’s killing.

“Murderer police, get out of Kurdistan!” some protesters chanted. “This is only the beginning, the struggle continues. The murderer state will pay!”

Turkish forces killed the man and wounded 10 others when they fired on a group protesting against the construction of a gendarmerie outpost in the Kurdish-dominated region.

The incident, in the Lice district of Diyarbakır province, appeared to be the most violent in the region since a ceasefire declaration in March by jailed Kurdish rebel chief Abdullah Ocalan in a decades-old conflict between his fighters and the Turkish state, and it risks derailing the nascent peace process.

About 10,000 protesters descended on Taksim Square, which has been the centre of weeks of anti-government demonstrations, but were prevented from entering the square by riot police.

Many in the crowd sat in the roads leading to the square after being denied entry. “Long live the brotherhood of the people!” people shouted in both Turkish and Kurdish.

Most of the protesters dispersed after a couple of hours, with a group of about 1,000 remaining near the square. Riot police pushed them away from the square with shields and slow moving water cannon trucks although no water was fired. Announcements were made for protesters to return to their homes.

The Kurdish tensions come at a time of increased vigilance among Turkish security forces after the anti-government protests in Istanbul, Ankara and other cities in which four people have died and thousands have been injured.

The protests, which had largely died down over the past week, have emerged as the biggest public challenge to prime minister Tayyip Erdoğan’s 10-year rule. He has dismissed the protesters as pawns of Turkey’s enemies and has called supporters to back his party in municipal elections next year.