Turkish Prime Minister Recep Tayyip Erdogan has said plans to redevelop a park in Istanbul will go ahead despite mass protests rocking the country.
Describing some of the demonstrators as "extremists", he said seven foreigners had been arrested over the unrest.
Mr Erdogan made the remarks in Tunis. He is to return to Turkey from a North African tour later on Thursday.
A large protest group has called for further demonstrations in response to the comments, correspondents say.
The demonstrators had hoped for a sign of compromise but Mr Erdogan's comments are likely to fan the flames of discontent, says the BBC's Mark Lowen in Istanbul.
The economic response was swift, with the stock market dropping nearly 5% after the prime minister's announcement.
The original sit-in at Gezi Park spiralled into nationwide unrest after police cracked down on activists defending the green space near Istanbul's Taksim Square from developers.
For days, demonstrators in Istanbul, Ankara and other cities have been calling for the three-term prime minister to quit.
His ruling Justice and Development Party has governed Turkey since 2002, winning a series of election victories.
They accuse his government of becoming increasingly authoritarian and trying to impose conservative Islamic values on a secular state.
Four people including a police officer are reported to have died, thousands have been injured and hundreds arrested in the unrest.
The foreigners detained on Thursday were from France, Germany, Greece, Iran and the US, Turkish Interior Minister Muammer Guler said.
'Implicated in terrorism'
Speaking in Tunis, Mr Erdogan acknowledged that police had used "excessive force" against activists at the original sit-in. But he said that a small group of extremists was now manipulating what had started as an environmental protest.
"Among the protesters, there are extremists, some of them implicated in terrorism," he told reporters.
Mr Erdogan also defended the urban development plan for Gezi Park.
"The project respects [Turkey's] history, culture and environment," he said. "What we are doing is to protect the rights of the majority and to preserve the beauty of Istanbul."
Tunisian riot police surrounded the Turkish embassy in Tunis during Mr Erdogan's visit, after local left-wing groups called for protests to show solidarity with the demonstrators in Turkey, the AP news agency reports.
Meanwhile several of Turkey's largest unions called for calm on Thursday.
"Violence and fighting don't solve anything, and they make it impossible to solve problems," the unions said in a joint statement.
In Istanbul, thousands of striking workers joined the demonstrations on Wednesday. They held banners addressed to Mr Erdogan reading: "This nation will not bow to you!" and "Taksim Square is everywhere!"
In the coastal city of Izmir, police have released about 30 people detained earlier for posting "misinformation" on Twitter, the state-run Anatolia news agency reports.
Mr Erdogan has called the micro-blogging site a "menace" used to spread "lies".
Earlier this week, Deputy PM Bulent Arinc apologised for police violence in the original protest, which took place a week ago.
Protest representatives who met Mr Arinc on Wednesday presented a list of demands, which included the dismissal of police chiefs, a ban on the use of tear gas, the release of detained protesters, the sacking of Istanbul's governor, and the scrapping of the plans for the redevelopment of Gezi Park.
Opponents of the plan say the park is of the few green areas left in central Istanbul - many had been camping out there for several days in protest.
But Mr Erdogan has repeatedly said the project would go ahead, and that the historic Ottoman-era military barracks would be rebuilt on the site as planned.
The protests come as Turkey prepares to host an international conference focused on its relations with the EU on Friday.
Mr Erdogan is to make the opening speech at the event, which will be attended by the EU's Commissioner for enlargement, Stefan Fuele, British ex-foreign minister Jack Straw and representatives from other member states.
France earlier condemned Turkey's heavy-handed police response to the protests.
Negotiations with the EU have stalled in recent years because of concerns over freedom of speech, treatment of religious minorities, women's and children's rights, civilian control of the military and long-running tensions with Cyprus.