US has approved a 1.1 billion dollar deal to service Qatar's F-15 fighter jets despite the diplomatic stand-off between the Gulf emirate and its neighbours. <br/><br/>The State Department said, it had approved the contract to service Qatar's F-15QA jets and build them ground facilities and hardened bunkers. <br/><br/>The new maintenance and training facilities will also come with improved cyber security services, mission critical computer resources, support services, force protection services.<br/><br/>Qatar is locked in a bitter dispute with Washington's other Arab allies in the region, led by Saudi Arabia.