 The Nationalist offensive was planned for December 10, but was postponed to December 23.On December 23, the Italians and the Navarreses crossed the Segre at Mequinenza, broke the Republican lines, and advanced sixteen kilometres, but they were stopped by the V and XV Republican corps led by Lister on December 25.On the left flank, Muñoz Grandes and Garcia Valiño advanced towards Cervera and Artesa, but they were blocked by the 26th Republican Division.