S. Viet Troops Begin Departure

South Vietnamese troops are moving towards their own territory from positions in Laos in what their officers say is the last stage of the incursion into Laos.

As the South Vietnamese withdraw from Laos, they face severe fighting. American helicopter support for South Vietnamese positions has been hindered by North Vietnamese artillery attacks and by poor weather conditions.

The withdrawal has been further complicated by the unauthorized departure of 15,000 South Vietnamese troops Monday night. South Vietnam sources, however, denied any mutiny, claiming that it had ordered the departure.

Ground fighting in Cambodia and South Vietnam continued to be light yesterday. Skirmishing was infrequent, with the most bitter action restricted to the Mekong Delta.