The first round of a vote that could lead to more than 130 members of the Turkish legislature losing their legal immunity began Tuesday, with the country's pro-Kurdish party calling the push an attack on its deputies.
Parliamentarians facing potential prosecution come from all four parties in parliament, but the pro-Kurdish Peoples' Democratic Party (HDP) would be most disproportionately affected, with about 50 of its 59 members in parliament at risk.
Committee-level discussions about the move - which is being organized by the ruling Justice and Development Party (AKP) - have led to fistfights. Debate in the main plenary is also likely to be heated.
The government says the move is intended to remove immunity from those who have existing police dossiers.
The HDP says it is being targeted under anti-terrorism laws. Those laws have been in the spotlight recently because Turkey is refusing to amend them to bring them in line with European standards.
The EU is insisting the change is needed if Turkish citizens will get visa free access to Europe's Schengen zone as part of a recently inked migration deal. The disagreement has resulted in a stand-off threatening the viability of the agreement.
"What this motion seeks to destroy is the HDP opposition in the parliament," Figen Yuksekdag and Selahattin Demirtas, the co-leaders of the HDP, wrote in a letter to European parliamentarians.
Both leaders face having their immunity lifted and accuse the government of a "totalitarian attack," warning that the moves against the Kurdish minority could lead more violence in a country that has already seen regular clashes in recent months.
Conflict between the state and the armed Kurdistan Workers' Party flared up again in 2015 after a two-year ceasefire collapsed. Many hundreds have since died, with the death toll rising daily, including both members of the security forces and civilians.
"Silencing democratically elected opposition MPs for their political statements is the obstruction of parliament and against democratic principles," a group of European Parliament members from several parties said in an open letter.
"Excluding democratically elected members of the parliament is not the way to deal with the Kurdish problem."
Turkey has doubled down on its insistence it will not change its anti-terrorism laws, which critics saw are wide and vague, leaving space for abuse by the authorities.
"Telling us to change our anti-terror law at a time when we are fighting against the PKK and Daesh amounts to supporting terrorism. We will never give into such impositions,” Foreign Minister Mevlut Cavusoglu said in Vienna, using a name for Islamic State.
Europe has been hoping to rely on Turkey to crack down on people smugglers bringing migrants, including Syrian refugees, to the bloc. Since the deal was agreed in March, there has been a significant drop in the number of new arrivals on the nearby Greek islands.
The government says the proposed bill lifting immunity would only target those who have police proceedings ongoing against them.
President Recep Tayyip Erdogan, a founder of the AKP - which has a majority of 317 seats in 550 member parliament - has repeatedly called for the immunity of HDP deputies to be lifted, accusing them of cooperating with the banned PKK.
"Neither we nor this nation can be expected to make an effort to tolerate deputies who do nothing but act as a mouthpiece for the separatist terrorist organization," he said in February, according to the state-run Anadolu news agency.
The AKP will need the support of other groups in parliament to push through the removal of immunity, as the motion proposed is a constitutional issue.
Turkish media have said the far right Nationalist Movement Party (MHP), which is staunchly anti-Kurd, will likely come on board. The centre-left People's Republican Party (CHP) could see some members vote in favour, though the party's chief has an existing dossier.
The final vote is not expected until Friday at the earliest, but could be pushed back as far as May 24.
To get a referendum on the matter, 330 members of parliament must vote in favour, while 367 are required for the constitutional change to pass in the house.