Dramatic CCTV footage appeared to show cars moving past a bus stop close to Ankara's main square before a massive ball of fire erupts, setting nearby vehicles ablaze as people run for cover.

A police source said the bomb had been packed with pellets and nails to cause maximum injury and carnage.

Turkish warplanes responded by pounding Kurdish rebel targets hours after Turkish President Recep Tayyip Erdogan vowed to bring terrorism 'to its knees'.

Police also detained dozens of suspected Kurdish militants in a southern Turkish city and imposed a round-the-clock curfew in the southeastern town of Sirnak in order to conduct operations against rebels there.

Security officials said one of two suspects was a woman who joined the PKK militant group in 2013.

They identified the woman as having been born in 1992 and being from the eastern Turkish city of Kars.

The other was a man whose severed hand was found 300 metres from the bast site.

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