A homicide bomber in a car attacked a convoy of foreign troops in the Afghan capital Sunday, but there was no immediate word on casualties, a police officer said. Taliban militants claimed responsibility for the attack.

The bomber targeted the convoy in Kabul's western outskirts, said Gen. Zulmay Khan Horiyakheil, a regional police commander. It was not clear if the bomber hit the convoy. Representatives for NATO and U.S. troops said they were checking the report.

A Taliban spokesman, Zabiullah Mujahed, claimed responsibility for the blast in a phone call to an Associated Press reporter in Kabul.

Insurgent regularly launch suicide attacks on foreign and Afghan troops throughout Afghanistan, but the number of such attacks in the capital has decreased over the past year.

There are some 70,000 U.S. and other NATO troops in the country.

President Obama's administration has indicated it is likely to send 30,000 additional troops in hopes of turning the tide of Taliban gains, and extending the control of the central government into the far reaches of the country.