Insurgents in Syria have seized at least four government airmen, the Syrian Observatory for Human Rights reports.<br /><br /> The capture purportedly took place after their helicopter came down in a rebel-held area in Idlib province. <br /><br /> Syrian Navy Mi-14 anti-submarine helicopter crashed in Idlib province (north west)<br />#Syria #alnusra pic.twitter.com/EZCaglyMqF— Tom Antonov (@Tom_Antonov) March 22, 2015<br /><br /> The British-based activist group said opposition fighters – including members of the al-Qaeda-affiliated Nusra Front – had killed one crew member and taken most of the rest prisoner. One person was said to be unaccounted for. <br /><br /> Images posted to social media sites purport to show the injured pilot being led away. <br /><br /> “@uygaraktas One of the Helicopter Crew member before the execution #Syria pic.twitter.com/wHFGM6JqL1“— ARnews 1936 (@ARnews1936) March 22, 2015<br /><br /> Images of a crew member and pilot of the downed regime helicopter in Idlib, Syria. pic.twitter.com/uTqlUloNyW— Breaking News (@NewsOnTh