Opposition party leaders claim a 22-year-old member of a political youth party has died after being shot during anti-government protests.
Turkish TV says Abdullah Comert was "seriously injured" during clashes in southern Turkey.
Hasan Akgol, a key member of the opposition Republican People’s Party, told NTV the man was a member of the youth branch.
His death, which hasn't been officially confirmed, follows that of a 20-year-old man who was killed after a taxi slammed into a crowd in Istanbul.
Eight people hurt in Ankara are also in critical condition.
It comes as Turkey's public sector workers union today begin a two-day strike to protest against what they have condemned as "state terror" against the demonstrations.
Strike
The strike by the 240,000-member Confederation of Public Workers' Unions (KESK) is likely to affect schools, universities and public offices throughout the country.
Turkish riot police fired more tear gas at protesters on a fourth night of violent clashes in Ankara and Istanbul.
Prime Minister Recep Tayyip Erdogan has rejected protesters' demands that he resign and claims the unrest is the work of Turkey's opposition.
He branded the demonstrators “extremists” in a move likely to further inflame the situation in the country.
Violence
Violent protests have rocked Turkey since Friday, when police launched a pre-dawn raid against a peaceful sit-in protesting against plans to develop Istanbul's Taksim Square.
Since then, the unrest - by mostly secularar Turks - has spiralled into Turkey's biggest anti-government disturbances in years.
In Istanbul, clouds of tear gas in the Besiktas area forced protesters to run for cover. Riot police deployed water cannons to keep protesters back.
Turkey's stock exchange dropped 10.5% on Monday over concerns about the destabilising effect of the protests.
US voices fears
The Obama administration has voiced concern over the crackdown on protesters, urging authorities to exercise restraint.
Secretary of State John Kerry said Washington is "deeply concerned" by the large number of people who have been injured.
Groups including Amnesty International and Human Rights Watch have denounced the police reaction as excessive.
Some 1,700 people arrested nationwide have now mostly been released, according to Interior Minister Muammer Guler.
