ISTANBUL (AP) - A group of protesters leading the sit-in at an Istanbul park said on Saturday their "struggle will continue," despite a warning and efforts from the prime minister to negotiate a peaceful end to two weeks of demonstrations that have devolved at times into clashes with riot police.

Taksim Solidarity, an umbrella group of protests movements, did not specify in its statement whether that meant the sit-in in Gezi Park in Istanbul would end, but said: "We shall continue to keep watch over our park."

Earlier on Saturday, President Abdullah Gul wrote on Twitter that "everyone should now return home", insisting "the channels for discussion and dialogue" have opened.

It was an apparent reference to talks on Friday between Prime Minister Recep Tayyip Erdogan and a small group of delegates from the protest.

In those talks, the prime minister promised to let the courts and a possible referendum decide the fate of a Gezi Park redevelopment project that has sparked Turkey's biggest protests in decades.

Overnight, police firing water cannons and tear gas dispersed protesters who erected street barricades near Turkey's parliament in the capital, Ankara. It was the latest face-off between authorities and demonstrators over the park redevelopment plan and the police handling of the earliest days of the protests.

Mr Erdogan's supporters were planning weekend pro-government demonstrations in Ankara and Istanbul.