ANKARA • Turkey's police, intelligence and security chiefs have been removed from their posts in what has been described as an effort to help the investigation into Saturday's bombings that killed more than 90 people.

The twin suicide bombings targeting a rally of pro-Kurdish activists and civic groups sparked anger from government opponents, who condemn the authorities for failing to prevent the worst attack of its kind on Turkish soil. Others accuse the government of complicity.

The Turkish Interior Ministry, when announcing the suspensions of the top officials, did not say if they would return to their posts after the investigation.

The announcement came hours after President Recep Tayyip Erdogan admitted there had been an intelligence failure which he said would be probed in investigations.

"There must undoubtedly be a mistake, a shortcoming in some place. Of what dimension? This will emerge after examinations," he told reporters on Tuesday.

The possibility that a group known to the authorities carried out the bombings has heaped pressure on the government, already under fire from opponents for failing to provide more transparent information on its investigations into explosions earlier this year.

Four people were killed in the bombing of a Peoples' Democratic Party (HDP) rally in the south-eastern city of Diyarbakir on the eve of the June elections. In July, a suicide bombing in Suruc near the Syrian border, which was blamed on the Islamic State in Iraq and Syria (ISIS), killed 33 mostly young pro-Kurdish activists.

The latest attack targeted thousands of people gathering for a peace rally of union, leftist and Kurdish activists criticising the government's current offensive against Kurdish militants.

The pro-Kurdish HDP, which lost several members in the blasts, has accused the authorities of, at the very least, severe negligence over the bombings.

In protests after the blasts, demonstrators have displayed banners such as "killer Erdogan" and "we know the killer!".

The authorities have angrily ridiculed claims of state complicity in the bombings.

The government has said that ISIS is the prime suspect behind the attack, which also injured more than 500 people.

Mr Erdogan yesterday made his first visit to the blast site outside Ankara's main railway station, laying flowers for the victims, alongside visiting Finnish President Sauli Niinisto.

The attack has raised political tensions to new highs as Turkey prepares for a Nov 1 snap election, with polarisation within the country now greater than ever.

REUTERS, AGENCE FRANCE-PRESSE