Turkey's deputy prime minister has offered an apology for a violent crackdown on an environmental protest, in a bid to appease days of anti-government rallies across the country as hundreds of riot police deployed around the prime minister's office in the capital.

Bulent Arinc, who is standing in for prime minister Recep Tayyip Erdogan while he is out of the country, said the crackdown was "wrong and unjust".

It was unclear whether Mr Arinc was giving the government line. Mr Erdogan, who is visiting Morocco, Algeria and Tunisia, has undermined statements by his ministers in the past. He has previously called protesters "looters" and dismissed the protests as acts by fringe extremists.

Thousands have joined anti-government rallies across Turkey since Friday, when police launched a pre-dawn raid against a peaceful sit-in protesting against plans to uproot trees in Istanbul's main Taksim Square. Since then, the demonstrations by mostly secular-minded Turks have spiralled into Turkey's biggest anti-government disturbances in years, and have spread to many of the biggest cities.

A 22-year-old man died during an anti-government protest on Monday in a city near the border with Syria, with officials giving conflicting reports on what caused his death.

The Hatay province governor's office initially said the man who died, Abdullah Comert, was shot during a demonstration in the city of Antakya. It backtracked after the province's chief prosecutor's office said a post-mortem examination showed Mr Comert received a blow to the head and there was no trace of a gunshot wound.

Governor Celalettin Lekesiz did not respond to a journalist's question as to whether the man might have died after being hit in the head by a gas canister. Mr Arinc said the government was taking "all measures" to ensure that similar "bad incidents" were not repeated as police subdued protests.

Protests were directed at what critics say is Mr Erdogan's aggressive and authoritarian style of governance. Many accuse him of forcing his conservative, religious outlook on lives in this mainly Muslim, but secular nation. He rejects the accusations, saying he respects all lifestyles and insisting he is the "servant" not the "master" of the people.

Mr Arinc said today: "In that first (protest) action, the excessive violence exerted on people who were acting out of environmental concerns was wrong and unjust. I apologise to those citizens."

He said the government was "sensitive" to the demands of the largely urban, pro-secular section of society that did not vote for Mr Erdogan's Islamic-rooted party. "I would like to express this in all sincerity: everyone's lifestyle is important to us and we are sensitive to them."