However, in February Wavell had been ordered to halt his advance into Libya and send troops to Greece where the Germans and Italians were attacking. He disagreed with this decision but followed his orders. The result was a disaster. The Germans were given the opportunity to reinforce the Italians in North Africa with the "Afrika Korps" and by the end of April the weakened Western Desert Force had been pushed all the way back to the Egyptian border, leaving Tobruk under siege. In Greece General Wilson's "Force W" was unable to set up an adequate defence on the Greek mainland and were forced to withdraw to Crete, suffering 15,000 casualties and leaving behind all their heavy equipment and artillery. Crete was attacked by German airborne forces on 20 May and as in Greece, the British and Commonwealth troops were forced once more to evacuate.