The US and Qatari navies today ended a three-day joint exercise involving nine vessels that took place at a time of high diplomatic tension between Doha and Gulf neighbours.<br/>'<br/>According to Staff Commander Mohammed Desmal Al- Kuwari among the tests carried out were air defence and surface missile simulation drills.<br/>'<br/>Qatari naval officer said the joint exercise was requested by the US Navy a few weeks back.He said that exercises involving Qatar and its allies would continue.<br/>'<br/>'''<br/>