The North Vietnamese southern advance inexplicably halted for three crucial weeks. While the northern crisis waned, however, General Du began to unravel, finding it increasingly difficult to make decisions. Vann gave up all pretext of South Vietnamese command, took over himself, and openly issued orders. He placed responsibility for the defense of the city of Kon Tum on the shoulders of Colonel Ly Tong Ba, commander of the 23rd Division. Vann then used massive B-52 strikes to hold the North Vietnamese at arm's length and reduce their numbers while he managed to find additional troops with which to stabilize the situation.