Giants. The mission to save americas majestic sequoias. See you at the top. This is the cbs weekend news. Ninan good evening. Im reena ninan with the western edition of the broadcast. Four more americans were killed today in afghanistan in a major breach of security. A suicide bomber blew themselves up inside the bagram airfield. Thats the largest u. S. Military base in afghanistan. The taliban claimed responsibility. Over the past 15 years, the United States has spent about 115 billion in aid for afghanistan. Thousand of american troops have given their lives. About 8500 remain. President elect trump will soon become the third u. S. Commander in chief to oversee u. S. Military operations for a war with no end in sight. Jonathan vigliotti has more from london. Reporter reena, afghan officials believe the suicide bomber entered on foot and hid behind local afghan Staff Members reporting for work this morning. Once inside the base, he successfully detonated his explosives. Four americans