On the night of 17–18 July, Montgomery renewed his attack toward Catania, with two brigades of Major General Kirkman's 50th Division. They met strong opposition and by 19 July Montgomery decided to call off the attack and instead increase the pressure on his left. The 5th Division attacked on the 50th Division's left but with no greater success, and on 20 July, the 51st Division, further west, crossed the river Dittaino at Sferro and made for the Gerbini airfields. They too were driven back by counter-attacks on 21 July. On the left flank, the 1st Canadian Division continued to advance but it was becoming clear that, as German units settled into their new positions in north eastern Sicily, the army would not have sufficient strength to carry the whole front and the Canadians were ordered to continue north to Leonforte and then turn eastward to Adrano on the south-western slopes of Mount Etna, instead of an encirclement of Mount Etna using Route 120 to Randazzo. Montgomery called forward his reserve division from North Africa, Major-General Vyvyan Evelegh's British 78th Infantry Division.