Turkey on Monday blamed Kurdish rebels for a suicide car bombing that killed 35 people in Ankara, the latest in a series of attacks that has heightened concerns about security in the country.
There has been no claim of responsibility for the Sunday evening blast, which reduced cars and buses to charred husks on a busy road in the heart of the capital, wounding more than 120 people.
But Prime Minister Ahmet Davutoglu said "serious, almost certain findings" from the investigation pointed to the outlawed Kurdistan Workers' Party (PKK) and vowed to "take any step required to defend this country".
Officials say that of the 37 people killed in the blast, 35 have now been identified as victims, one was a female suicide bomber and one a man thought to have been her accomplice.
Sunday's carnage, the second major bombing in Ankara in less than a month, will come as an embarrassment to the government of President Recep Tayyip Erdogan, whose Justice and Development Party (AKP) won parliamentary elections in November promising to save Turkey from "chaos" and smash the PKK.
In February a car bombing along very similar lines targeted military personnel in a nearby area of Ankara, killing 29 people.
A second attack so soon afterwards in the centre of the Turkish capital will add to security fears as Turkey grapples with the twin threat of Kurdish rebels and the Islamic State (IS) group.
The February attack was claimed by the Kurdistan Freedom Falcons (TAK), linked to the PKK, as revenge for Turkish military operations in the southeast. The TAK warned of more attacks to come, including on tourist areas.
Turkey has in recent months waged an all-out assault on the PKK, which launched an insurgency against the Turkish state in 1984, fighting for greater autonomy and rights for the country's largest ethnic minority.
Davutoglu said the evidence so far pointed to Kurdish rebels being behind the bombing.
"There are very serious, almost certain findings that point to the separatist terrorist organisation," he told reporters after visiting the wounded at an Ankara hospital, referring to the PKK.
Authorities have detained 11 people over the attack, Davutoglu said, while Turkish jets bombed PKK targets in northern Iraq on Monday, just hours after the blast.
Mourners wept as the first of the victims were laid to rest on Monday, some in coffins draped with the scarlet Turkish flag.
The country has been hit by a string of major attacks since the middle of last year, most of them blamed on IS, which controls large areas of Turkey's southern neighbour Syria.
Three have targeted Ankara, including a double suicide bombing in October that left 103 people dead.
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- 'We do not deserve this' -
Erdogan pledged to continue the fight against the Kurdish rebels and urged Turkey's allies to stop backing Syrian Kurdish groups -- which Ankara sees as branches of the PKK.
"Those at home and abroad who think they made us pay a price will pay real price themselves," he said in a televised speech on Monday evening.
But there was anger that security forces were unable to stop the blast, which came just two days after the US embassy warned of a possible plot to attack central Ankara.
"People have been talking about another bomb attack coming for more than a week but the government took no precautions and didn't warn anyone," Nihat Gorgulu, the uncle of one of the victims, told AFP.
"We are very afraid because the government doesn't care about the people of this country."
Kemal Kilicdaroglu, the head of the main opposition Republican People's Party, accused the government of "turning a blind eye" to the threat.
"We do not deserve this intolerable situation where parents are burying their children," he said.
The head of the pro-Kurdish HDP party Selahattin Demirtas suggested the government was "politically liable" for the attack.
"3 big explosions hit country's capital in the last 5 months, should we say we congratulate AKP for this? What should we say?" he said on the party's English-language Twitter account.
Dozens of left-wing activists protested in central Istanbul against the government over the bombing before riot police broke up the rally with tear gas, rubber bullets and water cannon.
Targeting civilians would not be a completely new tactic for Kurdish rebels, but would represent an escalation of the current phase of the conflict.
Can Acun, an analyst with Turkish think tank SETA, told AFP the rebellion appeared to be getting desperate.
"The 'uprising' launched by the PKK has not worked. Even the Kurdish population has distanced itself from its operations in the southeastern towns," Acun said.
"In frustration the PKK seems to have chosen to go for more serious acts."