An American soldier, a British soldier and one US contractor were killed Wednesday, a US official said, in the deadliest rocket attack in years on an Iraqi military base hosting foreign troops. On Wednesday evening, a volley of 18 rockets hit the Taji air base north of Baghdad which hosts troops from the US-led coalition helping local forces battle jihadists. The Iraqi military said the rockets were fired from the back of a truck, but it did not comment on any casualties.