Ankara - A suicide car bomb ripped through a busy square in central Ankara on Sunday, killing at least 34 people and wounding 125, officials said, the latest in a spate of deadly attacks to hit Turkey.
The blast at a bus stop near Kizilay square is the second major attack in the heart of the Turkish capital in less than a month, after a suicide car bombing on February 17 targeting the military that killed 29 people and was claimed by a dissident faction of the outlawed Kurdistan Workers' Party (PKK).
The fact that militants were able to strike again so soon in an area close to the prime minister's office, parliament and foreign embassies will raise fresh questions about Turkey's ability to manage the twin security threat posed by the Islamic State group (IS) and Kurdish rebels.
Health Minister Mehmet Muezzinoglu said the blast had killed 34 people and wounded 125 others, 19 of them seriously.
"Thirty people were killed on the spot and four others died in hospital," Muezzinoglu said after a meeting of ministers and security officials called by Prime Minister Ahmet Davutoglu following the blast.
Ambulances ferried the wounded from the square, a bustling commercial area and local transport hub, to 10 different city hospitals.
The force of the explosion, which hit at around 6:45 pm (1645 GMT), reduced numerous vehicles, including several buses, to charred husks and damaged nearby shops.
Interior Minister Efkan Ala said there were "one or two" attackers in the car and they deliberately targeted the bus stop, adding that officials had already gathered "important information in the investigation". But he held back from blaming any particular group.
There was no immediate claim of responsibility but Sunday's blast bore many similarities with the February bombing.
That attack was claimed by the Kurdistan Freedom Falcons (TAK), linked to the PKK, which said it was revenge for operations by the Turkish military in the southeast of the country.
A two-year ceasefire between the government and Kurdish rebels collapsed in the middle of last year and since December security forces have been waging a major campaign in the country's southeast against the PKK - listed as a terrorist outfit by Ankara and its Western allies.
President Recep Tayyip Erdogan said the government would "never abandon its right to legitimate defence against the terrorist menace." "Turkey is fighting a determined struggle against terrorist organisations," he said.
There was a narrow escape for Australia's ambassador to Turkey James Larsen, who Canberra said was in his car just 20 metres (yards) away from the bomb when it went off.
Turkey has been on high alert following a string of attacks since the middle of last year, most of them blamed on the IS group, including a double suicide bombing in Ankara in October that left 103 people dead.
As recently as Friday, the US embassy issued a warning about a possible plot to attack part of central Ankara, advising American citizens they should avoid the area.
Sunday's blast comes at a delicate moment for Turkey, as it seeks to persuade the European Union to speed up its path to membership of the bloc in return for help with the migrant crisis.
French President Francois Hollande condemned the "vile attack" and said France stood alongside Turkey in the fight against terror, while the US ambassador in Ankara, John Bass, said he was "deeply saddened and horrified" by what had happened.
British Prime Minister David Cameron said on Twitter that he was "appalled" by the attack.
After the blast a judge in Ankara banned the spreading of information about the attack online, particularly on social media sites, where photos and videos had been circulating.
As part of the anti-PKK offensive, strict curfews were imposed in December a number of Kurdish-dominated towns and cities and Sunday's attack came as these were extended to two more towns in the southeast as a prelude to fresh military operations.
Authorities said restrictions would be slapped on Yuksekova, near the Iranian border, and Nusaybin, on the frontier with Syria, to "restore order and security" following an increase in "terrorist activity".
Ankara has vowed to wipe out the PKK, classed as a terrorist organisation by Turkey and its Western allies, and has said "clean-up" operations in Yuksekova, Nusaybin and Sirnak, a third Kurdish city, are imminent.
After February's attack Erdogan rejected the TAK claim and insisted it was the work of the Syrian Kurdish People's Protection Units (YPG), which Ankara regards as a branch of the PKK.
The issue has driven a wedge between Ankara and its ally Washington, which works with the YPG as the only effective force combating IS in Syria.