Turkey police on Saturday began pulling out of Istanbul's iconic Taksim Square, the scene of a second day of violent clashes between protesters and police over a controversial development project.

Thousands of demonstrators flooded the site as police lifted the barricades around Taksim Excursion Park and began withdrawing from the square, an AFP reporter saw.

Turkish Prime Minister Recep Tayyip Erdogan said there had been cases of "extreme" police action against demonstrators protesting against a redevelopment project in an Istanbul park.

"It is true that there have been some mistakes, extremism in police response," Erdogan said after a second day of violent protests left dozens injured.

The interior ministry said in a statement that legal action would be taken against police officers acting "disproportionately."