Turkish opposition parties have vowed to block a security bill which triggered brawls in parliament twice this week, in a rare show of unity months before elections.
The government-backed legislation would bolster police powers to tackle violent demonstrations and broaden their scope to use firearms against protesters.
Lawmakers from the ruling AK Party exchanged blows with opponents late Thursday, pictures from the debate showed. One opposition deputy tumbled backwards down a flight of stairs. Another brought a helmet to the assembly after violence Tuesday.
"The fact that all three opposition parties are standing against this law with such vigour shows that the assaults of the government have become unbearable for all sections of society," Ali Riza Ozturk, of the main opposition CHP, told Reuters.
It has also become a battleground for Turkey's Kurds, who see the legislation as aimed at them, and risks derailing a fragile peace process to end a decades-long insurgency in the southeast.
Pervin Buldan, a senior member of the HDP, which draws most of its support from Kurdish areas, vowed her party would continue stalling the bill unless the government rethinks. If the opposition blocks the legislation until a likely parliament recess in late March, it may not pass before the June election.
The proposals would allow officers to use firearms against protesters wielding petrol bombs and other dangerous weapons.
They would also increase punishments for those participating in violent protest, and give governors appointed by Ankara greater powers to direct police in certain circumstances.
Turkish President Tayyip Erdogan and Prime Minister Ahmet Davutoglu have repeatedly accused the opposition of supporting violence and condoning the use of petrol bombs because of their opposition to the bill.
"The AKP will not yield to any provocation and this law will pass, one way or the other," Davutoglu said on Friday.
Former president Abdullah Gul, who jointly founded the AKP with Erdogan, called for the bill to be reviewed, however.
Emma Sinclair-Webb, a researcher at Human Rights Watch, said the legislation would take Turkey "toward a police state" and disputed government suggestions that the bill would bring it in line with European standards.
"It's really deceptive and cynical to say this is simply following EU norms, given the ugly picture we have of policing of demonstrations in Turkey," she told Reuters.