Turkey's ruling AK Party has won initial support in parliament for a constitutional change that could see pro-Kurdish and other lawmakers prosecuted, but failed to secure a strong enough majority for now to avoid a referendum, Reuters reports.

In a secret ballot late on Tuesday, May 17, 348 lawmakers in the 550-seat parliament backed the plan to lift MPs' immunity from prosecution, which critics say targets the pro-Kurdish opposition and could fan the flames of conflict between Kurdish militants and the state.

The assembly will now vote on the amendment in a second round of voting on Friday. The AKP needs 367 votes to change the constitution directly, 330 votes or at least 330 to put the measure to a referendum.

The bill triggered brawls in parliament this month between the members of AKP and the pro-Kurdish Peoples' Democratic Party (HDP), parliament's third-largest grouping, Reuters says.

The left-wing HDP has said the move is aimed at undermining its support and could disenfranchise its voters, drawn mainly from Turkey's Kurdish minority of 15 million people.