Turkey clashes: Thousands rally as PM Erdogan returns
Thousands of supporters of Turkish Prime Minister Recep Tayyip Erdogan have greeted him at Istanbul airport on his return from a North African tour.
Meanwhile, thousands of anti-government protesters have rallied again in Istanbul's Taksim Square.
Earlier, Mr Erdogan vowed to press ahead with a controversial proposal to redevelop a park in Istanbul.
A local protest against the plan turned into political unrest in Istanbul, Ankara and across Turkey.
The original sit-in at Gezi Park last Friday mushroomed after police cracked down on activists defending the green space near Taksim Square from developers.
For days, demonstrators in Istanbul, Ankara and other cities have called for the three-term prime minister to quit.
Mr Erdogan returned from Tunisia in the early hours after a four-day visit to North Africa.
Supporters waving Turkish flags descended on the airport to greet him, many chanting: "We are with you, Erdogan."
Hundreds of others marched through streets leading to the airport chanting: "Istanbul don't sleep, defend your leader."
Mr Erdogan addressed the huge crowd after landing.
Meanwhile, correspondents in Taksim Square say the atmosphere is good-natured, with protesters dancing and chanting political slogans.
Many are part of a secular, well-educated middle class which feels that Turkey lacks a proper, free political culture, the BBC's Jeremy Bowen, in Istanbul, reports.
Mr Erdogan is a pragmatic politician who has executed U-turns in the past, our correspondent says.
But judging by the tone of the language he used earlier, the prime minister seems not inclined to do so on this particular issue, he says.
Speaking in Tunis earlier, Mr Erdogan acknowledged that police had used "excessive force" against activists at the original sit-in. But he said that a small group 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."
The economic response to the remarks was swift, with Turkey's stock market dropping nearly 5% after the prime minister's announcement.
Meanwhile the US state department said Turkish officials should refrain from "unhelpful rhetoric and unhelpful comments that will not help calm the situation".
Since the protests erupted, four people, including a police officer, are reported to have died, thousands have been injured and hundreds arrested.
Among those detained were seven foreigners from France, Germany, Greece, Iran and the US, Turkey confirmed on Thursday.
Protesters accuse Mr Erdogan's government of becoming increasingly authoritarian and trying to impose conservative Islamic values on a secular state.
His Justice and Development Party has governed Turkey since 2002, winning a series of election victories.
Earlier this week, Deputy PM Bulent Arinc apologised for police violence in the original protest at Gezi Park.
He also met representatives from a protest group calling itself the Taksim Solidarity Platform (TSP).
The collective 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 one of the few green areas left in central Istanbul.
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 over Cyprus.