At the Battle of the Somme, 18 British armed reconnaissance planes strafed the enemy trenches after conducting surveillance operations. The success of this improvised assault spurred innovation on both sides. In 1917, following the Second Battle of the Aisne, the British debuted the first ground-attack aircraft, a modified F.E 2b fighter carrying bombs and mounted machine-guns. After exhausting their ammunition, the planes returned to base for refueling and rearming before returned to the battle-zone. Other modified planes used in this role were the Airco DH.5 and Sopwith Camel—the latter was particularly successful in this role.