 On 20 May the PAVN 141st Regiment attacked the base at Tan Khai and continued attacking unsuccessfully for 3 days against a determined defense before withdrawing.In mid-July the 21st Division was replaced by the 25th Division and they completed the destruction of the remaining PAVN strongpoints at Tau O by 20 July.On 13/4 June a regiment of the 18th Division was landed in An Lộc to reinforce the exhausted 5th Division.