A police official in Kabul says that a suicide car bomber has targeted a foreign convoy just a couple hundred yards (meters) from the U.S. Embassy.

Faird Afzalai, the chief of criminal investigations for Kabul's police, said Tuesday that the bomber targeted a foreign convoy, but he did not immediately have information about what kind of convoy or the number of casualties.

The blast happened on a busy road that runs from the U.S. Embassy to the airport. A white plume of smoke could be seen rising in the sky after a blast rattled windows in nearby neighborhoods.

The attack comes as the country's two presidential contenders continue negotiations to form some sort of national unity government.