More than 60 people have been wounded and at least 12 are dead following a fatal car bomb that exploded outside a hospital in the capital city of Kabul on Saturday, according to The Guardian.

It is believed that the suicide bomber targeted a convoy near the hospital. Three American contractors were killed in the attack, but most of those killed and injured were Afghan citizens. The three American contractors worked for DynCorp International, a U.S. security firm.

No terrorist group has claimed responsibility for the attack so far. Several buildings were damaged in the blast, with the hospital sustaining the most damage. The hospital was open at the time and treating patients, The Guardian reported.

The explosion occurred during afternoon rush hour in a busy city street, Ozarks First reported. Several women and children were injured in the blast. "Our thoughts and prayers are with the victims and their families who suffered as a result of this attack...The United States remains committed to assisting our Afghan partners in their efforts to ensure a peaceful future for Afghanistan," the U.S. Embassy in Kabul said in a statement.

The suicide car bomber struck a NATO convoy. The Taliban has denied involvement, according to The Olympian. The Taliban has attacked Kabul in the recent past, which has been rocked by multiple bombings this month.