A pro-Kurdish news agency says a Kurdish militant group has claimed responsibility for the car bomb attack in Ankara Tuesday that killed three people and wounded at least 15 others.

In an email sent to the Firat news agency Thursday, the Kurdistan Freedom Falcons said it carried out Tuesday's bombing and threatened more attacks in Turkish cities.

The Kurdistan Freedom Falcons is an offshoot of the Kurdistan Workers Party, or PKK. Turkey, the European Union and the United States regard the PKK as a terrorist group.

Tuesday's bomb attack took place near government buildings and a school, damaging cars and shops in the surrounding area. Interior Minister Idris Naim Sahin said the intent was to inflict as much harm as possible, as the blast occurred in an area of heavy car and pedestrian traffic.

The outlawed PKK has escalated attacks against Turkish targets in recent weeks. Last week, Kurdish rebels attacked multiple police facilities in southeastern Turkey, killing at least five people.

Turkish forces have responded by increasing their airstrikes against suspected rebel bases in northern Iraq. Last month, Turkey's military said it killed as many as 160 Kurdish rebels in air and artillery strikes across the border.

Turkish Prime Minister Recep Tayyip Erdogan has said Ankara's “patience is running out” with the rebels, who have waged a campaign for autonomy in the country's largely Kurdish southeast since 1984. The conflict has killed more than 40,000 people.