Erdogan initiated negotiations in 2012 to try to end the PKK’s fight for an autonomous state. The fighting has been largely fought in the predominantly Kurdish southeast and has killed 40,000 people since 1984. A fragile cease-fire had been in place since March 2013.

While Western allies have said they recognize Turkey's right to self-defense, they have urged it not to allow years of peace efforts with the PKK to collapse. The United States deems the PKK a terrorist organization, but it depends heavily on allied Kurdish fighters battling ISIL in Syria.

On Tuesday, Erdogan urged parliament to strip politicians with links to the PKK of immunity from prosecution — a move seen as aimed squarely at the HDP. On Wednesday, Turkey’s parliament was due to discuss the military operations in Iraq and Syria as well as Erdogan's call for the lifting of immunity.

Deputy Prime Minister Yalcin Akdogan, who has overseen the Turkish government’s efforts to settle its conflict with the PKK, accused the HDP of sacrificing the process in the name of political ambition. He said the group was more interested in winning enough votes to enter parliament than in working to resolve the conflict.

The HDP won 13 percent of the vote in a June 7 election, helping deprive Erdogan’s Justice and Development Party (AKP) of a majority in parliament for the first time since 2002 and forcing it to seek a junior coalition partner or face fresh elections.

"The HDP has destroyed the trust, has betrayed the peace process," Akdogan told the state-run Anadolu news agency. But he stopped short of declaring it definitively over. "It is unclear how the process will continue. First the PKK should put down weapons. If there's anything to be discussed, we can discuss it after that."

Many Kurds believe that by reviving the conflict with the PKK, Erdogan seeks to undermine support for the HDP before possible new elections. He has made no secret of his desire to change the constitution and amass stronger powers — which would be virtually impossible without a strong single-party AKP government.

The AKP has been holding coalition talks, but the leader of the largest opposition party, the CHP, said last week that he saw early elections as the most likely outcome.

"The president does not want a coalition to be formed. He knows that if a coalition is formed, whatever remains from his executive presidency dream will completely be destroyed," said Idris Baluken, a senior HDP lawmaker.

Al Jazeera and Reuters