A powerful explosion on Sunday shook Ankara, claiming at least 35 lives and injuring dozens of innocent civilians. The authorities identified one of the assailants as 24-year-old Seher Çağla Demir, who detonated a sports car loaded with explosives at the Turkish capital's main square. Demir, according to security sources, was a PKK member trained by the People's Protection Units (YPG ) fighters in northern Syria.

As Daily Sabah, we condemn Sunday's terror attack in the strongest terms, offer our condolences to the loved ones of terror victims and wish a speedy recovery to those who suffered injuries. But words have little meaning in the face of such senseless pain. We will not forget. We will not forgive. The punishment must be swift and severe - not only for armed militants but also their supporters and government officials proven guilty of negligence.

Sunday's attack was the latest in a series of recent terrorist acts that clearly prove that the PKK, along with its Syrian affiliates, are re-learning the rules of the terrorism trade from DAESH. The PKK leadership, which seldom ordered its militants to carry out suicide attacks against urban targets in the past, now uses suicide bombers with abandon.

In retaliation for the Ankara blast, the Turkish Air Forces launched airstrikes against PKK positions in Northern Iraq. At the same time, the security forces detained several dozen people with suspected links to the terrorist organization. But the price of a massacre must be much higher.

Let's start with the Peoples' Democratic Party (HDP):

When Abdülbaki Sömer blew himself up in Ankara less than a month ago, HDP representatives paid their respects to a suicide bomber who had killed dozens of innocent people. Their controversial visit to the suicide bomber's family was not an act of compassion but a blatant attempt to celebrate a mass murder. Having refused to co-sign a statement with Turkey's major political parties, HDP even refused to condemn its Van deputy Tuğba Hazer when she made provocative statements encouraging more Kurdish children to kill themselves to serve the PKK leadership's interests.

At this time, there is no point in sugarcoating the fact that the HDP leadership is directly responsible for the bloodshed that took place in Ankara on Sunday. This is what happens when a handful of out-of-touch revolutionary wannabes promote violence instead of channeling the Kurdish youth's energy into parliamentary politics. The Kurdish people supported the HDP to empower civilian leaders at the expense of armed militants. The party, in turn, has betrayed the people's trust by openly siding with terrorists. Demirtaş and his colleagues have not only radicalized young Kurds but also settled for a minor role in the PKK's bloody campaign. Keeping in mind that HDP deputies continue to shamelessly advocate terrorism, Parliament must take necessary steps to lift their immunity and deny them the opportunity to get away with murder. You crossed the line. The time has come to pay the price.

The HDP leadership's misguided policies, however, do not absolve Prime Minister Ahmet Davutoğlu's government of responsibility. Without further delay, authorities must launch an official investigation to identify their shortcomings and take necessary measures to make it possible for the intelligence community to prevent future attacks. The government, furthermore, must address the public's concerns by removing officials found guilty of negligence from their posts. Turkey needs a long-term strategy to de-radicalize the Kurdish youth, limit the PKK leadership's influence over local communities and promote unity against violence.

Finally, world leaders need to learn the lessons of PKK violence. Although many governments were quick to condemn Sunday's suicide attack, it doesn't change the fact that they have blood on their hands. The Middle East has been suffering from a toxic mix of terrorism and political instability for years and the international community's reluctance to take bold steps in Syria, coupled with the emergence of multiple failed states, proxy wars and no man's lands across the region, made it possible for terrorist organizations to recruit, train and indoctrinate brainwashed operatives. World leaders, in particular the European Union, have not only failed to address the refugee crisis but also left Turkey and others alone in the face of terror threats. Having killed hundreds of people in less than a year, the PKK remains free to operate and recruit across Europe. Whitewashing the organization's crimes by coming up with a hundred ways to distinguish them from the YPG just won't cut it. Five years into the civil war, the time has come for global players to step up and turn Syria, which has become an experimental playground of radical groups, around. The political transition must start without further delay if European governments do not want to watch their citizens bleed to death on the streets.

We expect the U.S., our strategic ally, will recognize Turkey's determination to eradicate terrorism and the destructiveness of PKK terror before too late. The U.S. needs to take action against the terrorist group rather than shed crocodile tears while the monster it rears turns around and bites its ally, which has stood by its side through thick and thin.