The female suicide bomber has been identified, Turkish Deputy Prime Minister Numan Kurtulmus said, but he did not provide further details about the bomber's background.
Investigators say they expect to identify the suspected male attacker pending the outcome of a DNA test.
Eleven people have been detained in relation to Sunday's bombing in Ankara
, Kurtulmus said, and 10 more remain at large.
As part of their investigation, authorities have been tracing a network connected to the female suicide bomber, he said.
"At this point in the investigation, the network of the woman who has definitively been identified as the suicide bomber, has been uncovered and is continuing to be uncovered," he said.
Although the government has not officially blamed the PKK, or the Kurdistan Workers' Party, for carrying out the suicide attack,Turkish Prime Minister Ahmet Davutoglu told reporters Monday that the evidence uncovered in the investigation very strongly indicates a "separatist terrorist organization" is responsible.
Raids targeting terror
Turkish authorities arrested at least 29 people in anti-terror raids and fighter jets struck Kurdish separatist targets in Iraq on Monday. Turkey's semiofficial Anadolu agency reported the terror sweeps and airstrikes.
Four people have also been detained in the southeastern city of Sanliurfa in connection with the vehicle used in the bombing, Anadolu reported. Security forces said the vehicle was purchased there, the news agency said.
Turkish President Recep Tayyip Erdogan vowed to bring those responsible for Sunday's attack, which targeted a transit hub, to justice. The country will bring "down terror to its heel," he said.
"Terror organizations and their pawns are targeting our innocent citizens in the most immoral and heartless way as they lose the fight against our security forces," Erdogan said in a statement.
"Terror attacks -- which intend to target the integrity of Turkey, unity and solidarity of our people -- do not diminish our will to fight against terror, but further boost it."
Last week, the U.S. Embassy in Ankara warned of a plot to strike government buildings not far from Sunday's attack site.
"I suspect (the government) had some indication that there was going to be an attack ... but they probably weren't able to narrow it down," CNN military analyst Rick Francona said. "The U.S. Embassy decided to err on the side of caution and go out and put out the warning anyway."
Authorities haven't released details about who they believe was behind the blast.
"It's too early to talk about who carried out this attack. The investigation is ongoing," a senior Turkish official said. "Our priority right now is the wounded."
Change of focus
Curfews were declared for two areas of southern Turkey, imposed "due to escalating terror activity in the region" and to ensure the "security of citizens' lives and property," according to the news agency
, quoting statements from the governors' offices of Hakkari and Mardin provinces.
Assigning responsibility for the attack could be difficult, but it could stir Erdogan to take an even tougher stance toward Kurdish separatists, CNN intelligence and security analyst Bob Baer said.
"Erdogan is already a bit of an authoritarian, and this is going to push him into a full-on war with the Kurds," he said.
Following the attack, the Turkish Radio and Television Supreme Council banned the broadcast of any images showing the moment and direct aftermath of the explosion. It also barred graphic images such as those of dead bodies at the scene of the attack.
The country's Internet watchdog also banned the release of video and photos of the blast on social media. Some inside the country -- including CNN's team on the ground -- could not access Facebook or Twitter for hours after the blast.
Turkey has banned social media sites in the past.