Turkish president Recep Tayyip Erdogan has vowed to bring terrorism "to its knees" following the suicide car bomb attack in the capital that killed at least 34 people and injured 125 others.

Mr Erdogan also said Turkey would use its right to self-defence to prevent future attacks and called for national unity.

"Our people should not worry, the struggle against terrorism will for certain end in success and terrorism will be brought to its knees," he said.

Turkey's prime minister Ahmet Davutoglu has postponed a visit to Jordan following the deadly bombing in Ankara.

The car bomb targeted people milling near bus stops in the heart of Ankara, killing the two suspected bombers, one of whom was a woman, a senior government official said.

Thirty victims were killed at the scene and four others died in hospital. Nineteen of the injured were said to be in a serious condition.

Police suspect Kurdish militants carried out the attack based on "initial indications", the government official added.

Interior minister Efkan Ala said Sunday's attack would not deter the country from its fight against terrorism.

British prime minister David Cameron said he was "appalled" by the atrocity, tweeting: "My thoughts are with all those affected."

US State Department spokesman John Kirby said: "We reaffirm our strong partnership with our Nato ally Turkey in combating the shared threat of terrorism."

Nato secretary general Jens Stoltenberg said: "There can be no justification of such heinous acts of violence."