The Turkish Interior Ministry said Wednesday it removed the Ankara police, intelligence and security chiefs from their posts in an effort to help the investigation into Saturday's bombings, which killed 97 people.
The twin suicide bombings, targeting a rally of pro-Kurdish activists and civic groups, sparked anger from opponents of the government who condemned it for failing to prevent the worst attack of its kind on Turkish soil. Others accused the government of complicity.
"In order to run a healthy investigation into the abominable terrorist attack ... and in line with the requests from chief civil and police inspectors, Ankara's provincial police chief, intelligence department chief and security department chiefs have been removed from duty," a statement on the ministry's website said late on Tuesday.
The statement did not say if the officials would to return to their posts after the investigation.
The announcement came hours after President Recep Tayyip Erdogan admitted that there was an intelligence failure, which he said would be probed in investigations.
Meanwhile, Turkish officials said police detained two people who posted tweets suggesting there could be a bomb attack in the capital Ankara a day before the twin suicides bombings. A government official said the two suspects had ties to the Kurdish rebels engaged in renewed fighting with Turkey's security forces. Saturday's rally was organized to call an end to the fighting.
The two suspects allegedly posted tweets that read, "The bomb will explode in Ankara" and "What if [ISIL] explodes [a bomb] in Ankara?"
The two suicide bombings came just weeks before Turkey's Nov. 1 elections, which are effectively a rerun of inconclusive June voting. The bombings raised fears that Turkey — a member of NATO, a candidate for European Union membership, a neighbor of war-torn Syria and the host for more refugees than any other nation — may be heading toward a period of instability.
On Tuesday protesters in trade-union-organized rallies were not permitted by the Istanbul governorship to march to Beyazit Square because of security concerns. At Sirkeci train station the protesters held a sit-in, and lawmakers made speeches; at Cerapasa Hospital there were tensions when police blocked people from marching.
The possibility that a group known to authorities carried out Saturday's attack has heaped pressure on the government, already under fire from opponents for failing to give more transparent information on its investigations into bombings in Diyarbakir and Suruc earlier this year.
Four people were killed in the bombing of a Peoples' Democratic Party rally in the southeastern city of Diyarbakir on the eve of June elections. In July a suicide bombing blamed on the Islamic State in Iraq and the Levant (ISIL) in Suruc, near the border with Syria, killed 33 people, mostly young pro-Kurdish activists.
Turkish Prime Minister Ahmet Davutoglu said ISIL was the main focus of the investigation, and on Tuesday, Erdogan said the country had intelligence suggesting that fighters from Syria were planning to carry out attacks in Turkey, adding that no groups were being ruled out in the investigation.
"There is certain intelligence about some preparations that were made by [people] entering our country and carrying out various acts — and that they originated from Syria," Erdogan said.
He rejected suggestions from a pro-Kurdish party that the state may have had a hand in Saturday's attack, which targeted left-wing opposition supporters and Kurdish activists, saying the accusations were based on gossip.