ISTANBUL (AFP) - Thousands of angry demonstrators descended on Istanbul's Taksim Square on Tuesday where a heavy police presence reigned after a day of clashes between riot officers and protesters in a sharp escalation of nearly two weeks of anti-government unrest.

Hundreds of police stormed the square, the epicentre of the nationwide protest movement, in the early morning, reclaiming the area after pulling out more than a week ago and catching protesters by surprise.