diplomat dies in mortar attack Baghdad, Oct 25, SPA -- In their boldest and deadliest ambushyet, insurgents waylaid three minibuses carrying U.S.-trained Iraqi soldiers heading home on leave and massacred about 50 of them _ forcing many to lie down on the ground and shooting them in the head, officials said. Some accounts by police said the rebels were dressed inIraqi military uniforms. The killing of so many Iraqi soldiers _ unarmed and incivilian clothes _ in such an apparently sure-footedoperation reinforced American and Iraqi suspicions that thecountry's security services have been infiltrated byinsurgents. A claim of responsibility posted on a Web site attributed the attack to followers of Abu Musab al-Zarqawi. Elsewhere, a U.S. diplomat was killed Sunday morning whena rebel-fired rocket or mortar shell crashed onto anAmerican base near the Baghdad airport, the U.S. Embassyannounced. Edward Seitz, 41, an agent with the State Department'sBureau of Diplomatic Security, was believed to be the firstU.S. diplomat killed in Iraq since the war began in March2003. A Bulgarian soldier was killed and two others were woundedin a car-bombing near Karbala, the Bulgarian DefenseMinistry said. Karbala, a Shiite holy city south ofBaghdad, has been quiet for months after U.S. troops routedShiite militia there last spring. The Iraqi soldiers were killed on their way home aftercompleting a training course at the Kirkush military campnortheast of Baghdad when their buses were stopped Saturdayevening by rebels near the Iranian border about 150kilometers (95 miles) east of Baghdad, Interior Ministryspokesman Adnan Abdul-Rahman said. There was confusion over precise figures, although theIraqi National Guard said 48 troops and three drivers werekilled.--SPA1155 Local Time 0855 GMT www.spa.gov.sa/213163