Turkish riot police walk past a burning barricade during clashes with anti-government protesters in Ankara.

Istanbul - Protesters clashed with police across Turkey overnight despite an apology for police violence from the deputy prime minister designed to halt an unprecedented wave of protest against Prime Minister Tayyip Erdogan.

Deputy Prime Minister Bulent Arinc was due to meet on Wednesday with organisers of the original demonstration against plans to build a replica Ottoman-era barracks on Istanbul's Gezi Park in Taksim Square. But he refuses to talk to unnamed groups he accuses of exploiting the situation to foment violence.

On Taksim itself, now focus of broader protests against what many see as Erdogan's increasingly authoritarian style of government, thousands remained at a makeshift camp despite rain. On a street off the square some skirmished with police who used tear gas.

On Tuesday, Arinc apologised for “excessive violence” by police against the original demonstration in an effort to defuse the unrest, comments which contrasted sharply with Erdogan's defiant dismissal of the protesters that, if anything, had appeared to inflame protest over the weekend.

Erdogan, who has won three successive general elections and enjoys a large parliamentary majority, left on Monday on a visit to north Africa.

US Vice-President Joe Biden, reflecting concern about stability in a key US Middle Eastern ally, urged the Turkish government to respect the rights of political opponents.

“Today's Turkey has a chance to demonstrate that there's no need to choose between economic advancement and democracy, the system that empowers the winners of elections and yet protects whose who are in opposition,” Biden said.

The United States has held up Erdogan's Turkey as an example of an Islamic democracy that could be imitated throughout the Middle East. But domestic opponents argue that, for all the economic advances under him and early democratic reform, events have recently taken a more authoritarian turn.

They also accuse him of pursuing an “Islamist” agenda by easing restrictions on the wearing of headscarves - symbol of female islamic piety - in state institutions, limiting alcohol sales and promoting broader religious projects. Erdogan denies any ambition to undermine the country's secular constitution.

Clashes spread overnight to the eastern province of Tunceli, where police fired tear gas and water cannon at hundreds of protesters who set up barricades and threw stones at them, witnesses said.

Police intervened in a similar way against demonstrators in the capital Ankara, as well Hatay province on the Syrian border where a 22-year-old man died after being hit in the head at a rally late on Monday.

The DISK union confederation, including unions in the metalworking, health and energy sectors, was due to stage a walkout on Wednesday, joining another labour confederation in a protest against the government. - Reuters