Bombs set off by two suspected suicide attackers ripped through a crowd of leftist and pro-Kurdish activists at a peace rally on Saturday, in the deadliest such attack in Turkey's recent history.
"The bombings were an attempt to influence the forthcoming elections, due to take place on 1 November after a vote in June left no party able to form a government," said the prime minister.
No group has yet claimed responsibility for the attacks, but the government believes that two male suicide bombers caused the explosions.
The funerals of more of the victims are taking place on Monday.
President Recep Tayyip Erdogan denounced what he called a "heinous attack" targeting "our unity and our country's peace".
Read More: Turkey: Toll from twin Ankara blasts soars to 95
Declaring three days of mourning, Davutoglu said there were "strong signs" the attack was carried out by two suicide bombers. International condemnation of the bloodshed was swift.
German Chancellor Angela Merkel expressed "sadness and dismay" over the attacks, while US President Barack Obama and Russia's Vladimir Putin offered their condolences to Erdogan.