'Terrorists' at Turkey demos: Erdogan

He said seven foreigners implicated in the unrest had been arrested.

"Among the protesters, there are extremists, some of them implicated in terrorism," Erdogantold reporters in Tunis, on the final day of a north African tour that has been oversha dowed by the unrest back home.

"Supporters of this terrorist organisation were present" in Istanbul's Taksim Square, epicentre of the protests, he added.

He did not specify the nationalities of the detained foreigners or where they had been arrested.

"Seven foreigners have been implicated in the unrest, six of whom have appeared before the public prosecutor and one of whom is under arrest.

"An inquiry is taking place to determie the manner in which they took part in the violence," the prime minister said.

Since last weekend, thousands of angry demonstrators opposed to the conservative policies of Erdogan's Islamic-rooted Justice and Development Party (AKP) have taken to the streets of Turkey's main cities calling for him to quit.

A heavy-handed police response to a peaceful demonstration against the redevelopment of Istanbul's Gezi Park next to Taksim Square was the initial spark for the nationwide unrest that has now claimed three lives.

Erdogan has previously defied the protesters, dismissing them as "extremists," and on Thursday he defended the urban development plan.

"The project respects (Turkey's) history, culture and environment... What we are doing is to protect the rights of the majority and to preserve the beauty of Istanbul," he said, adding that he did not link the environmental activists to the unrest.