SAS in secret war against Iranian agents

"TWO SAS soldiers rescued last week after being arrested by Iraqi police and handed over to a militia were engaged in a “secret war” against insurgents bringing sophisticated bombs into the country from Iran.
The men had left their base near the southern Iraqi city of Basra to carry out reconnaissance and supply a second patrol with “more tools and fire power”, said a source with knowledge of their activities.

They had been in Basra for seven weeks on an operation prompted by intelligence that a new type of roadside bomb which has been used against British troops was among weapons being smuggled over the Iranian border."
Times Online