Türkiye's pro-Kurdish Peoples' Democratic Party (HDP) and its allies will not field a presidential candidate in May, its co-leader said on Wednesday, raising the prospect of the opposition uniting against President Recep Tayyip Erdogan's re-election bid. Speaking at a news conference, Pervin Buldan did not openly say whether her alliance would support opposition candidate Kemal Kilicdaroglu, after they had met on Monday. Former HDP co-leader Selahattin Demirtas, who has been in jail since 2016 over what the party says are political reasons, has previously voiced support for Kilicdaroglu, who is the leader of the main opposition Republican People's Party (CHP). The HDP is the third-biggest party in parliament with more than 10% support nationwide and is seen playing a decisive role in the presidential election on May 14. "In the presidential elections, we will carry out our responsibility against the one-man rule," Buldan said, adding that they will work to instate basic rights and justice in Türkiye. "For these reasons, we are sharing with the public that we will not field a candidate in presidential elections." Erdogan is facing the biggest challenge to his rule in his more than two decades of leading Türkiye. Recent polls show him trailing Kilicdaroglu, the candidate of the opposition alliance of six parties. But the HDP votes will be crucial for the opposition to secure a majority in parliament in the vote on the same day and exceed the 50% required to elect the president. In 2019, the HDP cooperated with the opposition to defeat the ruling AK Party's mayoral candidates in major cities, including Ankara and Istanbul. The HDP has faced a crackdown since the collapse in 2015 of Ankara's peace process with the militant Kurdistan Workers Party (PKK), designated a terrorist group by Türkiye and its Western allies. Thousands of HDP members, lawmakers and mayors have been jailed or stripped of their positions in recent years over alleged links to terrorism, which the party denies.