Anakara’s police, intelligence and security chiefs have been suspended in the wake of bombings that left 97 people dead in Turkey’s capital, the BBC reports.

The interior ministry said the move would enable a “robust” investigation.

The attack, the worst in Turkey’s modern history, triggered widespread anger against the government.

Turkey’s president visited the site of the bombing on Wednesday. The prime minister said both Islamic State and the PKK could have played a role.

Turkish officials have said two suicide bombers carried out Saturday’s attack, which targeted crowds gathering for a rally against violence between Turkish government forces and the outlawed PKK (Kurdistan Workers Party).

Authorities said on Wednesday that they had detained two people with alleged ties to the PKK on suspicion of having prior knowledge of the attack.

Initially, Prime Minister Ahmet Davutoglu said IS, the PKK and far-left groups were all capable of such an attack. On Monday, he said IS was the prime suspect.

President Recep Tayyip Erdogan laid flowers for the victims as he visited the site of the attack with Finnish President Sauli Niinisto.