At least three people including a police officer were killed Sunday in a bomb attack targeting a police vehicle in Kandahar, in the Taliban's southern Afghan stronghold, an official said.
Shortly before the breaking of the day's Ramadan fast, a parked motorcycle "packed with explosives" exploded after being remotely detonated as the vehicle passed by, said Samim Khpalwak, spokesman for the governor of Kandahar province.
Three people -- two civilians and a police officer -- were killed and 13 others wounded, he said.
Provincial police spokesman Zia Durrani put the death toll at four and 12 wounded.
No group immediately claimed responsibility for the bombing, but it comes amid rising violence in Afghanistan, including in the capital Kabul.
Taliban insurgents launched a countrywide offensive in late April, stepping up attacks on government and foreign targets in what is expected to be the bloodiest fighting season in a decade.
The surge in attacks has also taken a heavy toll on civilians, according to the UN mission in Afghanistan.
Almost 1,000 civilians were killed during the first four months of this year, a sharp jump from the same period last year, it said.
NATO's combat mission to Afghanistan formally ended in December but a small follow-up foreign force of about 12,500 mainly US troops has stayed on to train and support local security personnel.