An Israeli patrol battled Arab fighters in southern Lebanon, and the Israelis sent an armored unit to help, sparking rumors of an invasion. The Israeli army said its troops fought guerrillas in the foothills of Mt. Hermon and that one soldier was slightly wounded. A Lebanese military spokesman said at least six guerrillas were injured. Israeli military officials would not deny reports from Beirut that Israeli tanks backed by helicopter gunships struck at pro-Iranian Shia Muslim guerrillas in the village of Maydoun, at the southern tip of the Syrian-controlled Bekaa Valley. A U.N. official who was in the area said there were fears of an invasion in southern Lebanon after the Israelis sent an armored unit to rescue its wounded soldier.