Before advancing into southern Abyssinia, General Brink was compelled to protect his western flank and to deny water sources to the Italians. For this reason, on 16 January the 1st Natal Mounted Rifles (of the 2nd Brigade), No 2 Armoured Car Company, 12 SA Field Battery and two irregular companies attacked the string of wells at El Yibo and El Sardu in the Kenyan Northern Frontier District. After three days of fighting, supported by the SAAF, the enemy withdrew from El Yibo on the night of 17 January and on the afternoon of 18 January, the 2nd Field Force Battalion, which had been moved up from the brigade reserve, entered an abandoned El Sardu. With the only water sources in the area in the hands of the South Africans, the advance into Abyssinia could commence.