A bomb blast rocked the centre of the Turkish capital Ankara on Tuesday and some media reports said two people were killed, while a local mayor said nobody was dead but three people were seriously wounded.
Police were not immediately available for comment, but a television station reported that the explosion had occurred in a minibus.
Television images showed several parked cars ablaze in front of a local state authority's office, while a plume of thick smoke rose over the area.
Ambulances and fire engines rushed to the scene. The state-run Anatolian News Agency said police had set up a security cordon at the site in case of a secondary explosion.
Dogan News Agency quoted police sources as saying the blast had been caused by a bomb and fire service officials as saying that two people had died. It also reported that police had detained a woman near the scene.
Cankaya Mayor Bulent Tanik said nobody had been killed but that three people had been seriously wounded, while broadcaster CNN Turk reported that 20 people had been wounded and were being treated at three hospitals. According to CNN Turk, bomb disposal teams were at the scene.
It was not immediately clear what caused the blast in the downtown Kizilay district, but a local mayor, Bulent Tanik, said an eyewitness had told him that someone had thrown a burning gas canister onto the vehicles from a nearby building.
"An investigation is underway," Tanik said. "If true, that canister might have triggered the blast of a liquefied petroleum gas tank on a vehicle." One of the vehicles was totally consumed by fire and four others were also damaged, television images showed.
NTV Television said ten people had been hospitalized. Tanik said three people had been seriously injured and some of them might have lost limbs.
The blast occurred near a school but no students had been harmed, Tanik added.
The injured were initially treated in a schoolyard by passers-by before medics rushed to the scene and whisked them away to hospitals, NTV television reported.
Interior Minister Besir Atalay inspected the scene of the blast, but police have yet to issue an official statement.
Kurdish, leftist and Islamic militants have carried out bomb attacks in Turkey in the past.