TEGUCIGALPA, Honduras (AP) _ At least 26 children and seven adults including an American missionary drowned Sunday when a flash-flood caught their school bus as it was fording a rain-swollen river, authorities said.

Three children were rescued after the bus overturned in the roiling waters of the Rio Grande about 80 miles southeast of Tegucigalpa and four children were still missing, said Lt. Frank Medina, a National Fire Department spokesman.

Among the dead was American missionary Dorothy Saunder Hood, 52, Medina said by telephone. Mrs. Hood is the wife of the Rev. George B. Hood, a U.S. missionary active in Honduras for many years.

Mrs. Hood was driving the bus, said relatives in Lancaster County, Pa., where she was born and raised.

Red Cross spokesman Jordan Peralta said the accident occurred on a country road between the villages of El Naranjal and Cantarranas.

''The vehicle was carrying 33 preschool children, between 3 and 6 years old, and seven adults,'' he said by telephone.

The children were on their way back to El Naranjal from a party at Cantarranas, a few miles away. Peralta said the bus was fording the usually shallow river when a flood wave crested over the bus and tumbled it downstream.

There is no bridge over the river on that road.

''The accident occurred when the vehicle was in the middle of the river ... and it was dragged along with all the passengers,'' Peralta said.

Peralta said the bodies were brought to the Central Morgue in Tegucigalpa for identification.