A BSF officer was killed in firing by Pakistan in Jammu and Kashmir's Rajouri district on Sunday evening, officials said.Pakistani troops fired two mortar rounds around 6.30 p.m., in which Sub-Inspector Chuni Lal of the Border Security Force (BSF) was killed, officials said.Meanwhile, in another incident in Sabjiya sector of Poonch district, two civilians were injured when they stepped on some explosive material which blew up. The condition of one of them is said to be critical.