KANDAHAR, Afghanistan, Dec. 17 (Xinhua) -- A car bomb explosion struck a NATO-led coalition forces' convoy in Kandahar city, capital of southern province of Kandahar on Sunday, a local official said.

The blast occurred at around 02:00 p.m. local time in Police District 5 of Kandahar city, along a road which connects the city to the international airport, the source told Xinhua anonymously.

"The explosion caused panic among the residents. We still cannot provide details on causalities. There is fear of possible causalities among the bystanders but details will be shared with media by officials later in the day," he said.

"We heard a huge blast when a convoy of international forces was passing our neighborhood. The whole place has now been sealed off, and no one knows what happened to residents near the blast site," witness Ahmad Ullah told Xinhua.

No group has claimed responsibility yet for the attack, but the Taliban insurgent group routinely claims responsibility for such attacks.