(AGI) Beirut, Sept 16 - Islamic State jihadists shot down aregime fighter plane in the skies over Raqqa, their Syrianstronghold, on Tuesday, reported the Syrian Observatory forHuman Rights. This was the first fighter plane downed since theregime started its air raids against ISIS in July, after itsproclamation of a caliphate on June 29. The city of Raqqa inthe Euphrates River valley, is the only region completely outof the government's control. . .