PKK member Nurettin Demirtaş, Peoples' Democratic Party (HDP) Co-Chair Selahattin Demirtaş's brother, has said that the main opposition Republican People's Party (CHP) must stand with the HDP against President Recep Tayyip Erdoğan and the ruling Justice and Development Party (AK Party).

Speaking to PKK-linked Fırat News Agency on Sunday, Nurettin Demirtaş, whose PKK membership was admitted by his brother in May 2015, said that the CHP must forge an alliance with the HDP by the experience gained from the Turkish War of Independence. He said: "For this reason, calls that have been made to the CHP are significant, but those who consider themselves as real progressives and democrats must not waste any moment in a CHP that abstains from such [an alliance]."

In a statement to a PKK-linked website, Bese Hozat, a senior PKK figure, made a similar call: "It is very important for the CHP to also develop an accurate and genuine self-critique and join the democracy struggle, standing with the HDP."

Another senior PKK leader, Mustafa Karasu, also previously urged the CHP into the struggle against the AK Party.

Using the pen name Hüseyin Ali in the pro-PKK Turkish daily Özgür Gündem, Karasu demanded support from the CHP, saying in his column that if they could count on "an important part of the CHP in this struggle, the AK Party government would be unable to even look for a place to hide."

CHP Deputy Chairman Sezgin Tanrıkulu, a deputy for Istanbul, also raised eyebrows when he appeared on a program on the PKK-affiliated Germany-based MED Nuçe TV channel earlier on the same day as the Ankara bombing, on Mar.13.

CHP Chairman Kemal Kılıçdaroğlu came under fire after making a statement in December that called terrorists digging trenches in urban areas of the country's southeastern provinces "friends."

In a live debate on Habertürk in January, CHP Mersin Deputy Aytuğ Atıcı called PKK terrorists who had been killed "martyrs," and allegedly justified young children leaving for the mountains to fight alongside the PKK.