Over the next two weeks PAVN forces kept up a barrage of artillery, mortar and small arms fire on the ARVN positions and infiltrated small units across the river in boats.[1]: 65 On 7 April the Marines withdrew from Đông Hà leaving the defense to the 57th Regiment, the 1st ARVN Armored Brigade, 20th Tank Battalion and the 4th and 5th Ranger Groups.[4]: 68