As summer school classes began in the District this week, students who would rather have been outdoors were not the only unhappy ones.

At Sousa Middle School in Southeast Washington, a handful of parents picketed yesterday, saying there were not enough teachers to accommodate the number of children. Meanwhile, the summer school principal was fuming that more than 100 children had walked out Tuesday, the first day of classes, after a parent told them incorrectly that asbestos made the building unsafe.

The discord at the school was an unusually dramatic example of the logistical challenges facing D.C. school officials in the summertime. Even as they renovate school buildings and update curricula, D.C. officials are providing education to 6,903 pupils -- more than one-tenth of the student population -- who have signed up for the six weeks of summer instruction.

As of Tuesday, school officials believed that 6,041 students were enrolled in summer school. "I am very pleased at coming across very well-organized conditions at the numerous summer school sites where I visited this morning," Interim Superintendent Robert C. Rice said in a statement that day.

But by yesterday, the number of students had risen sharply because of late enrollments, and school officials said they were sorting out how many teachers were needed at each site.

"We have had, in some cases, to shift teachers around," said Arthur L. Curry, the administrator who oversees the summer school program.

Most students attending summer school are studying intensive math or English to avoid being held back or are taking classes they did not complete so they can graduate on time. Also eligible are some students taking English as a second language and special education students who require year-round instruction. Classes are held from 8:30 a.m. to 12:30 p.m.

At Sousa, perched on the northern edge of Fort Dupont Park, the trouble began virtually the moment summer classes were supposed to start.

Keith T. Stephenson, the summer school principal, said that weeks ago he had expected to have 19 teachers because officials were anticipating an enrollment of 350 students at the school. However, Stephenson said he learned early Tuesday that fewer than 150 students had enrolled and that only six teachers were coming.

At 8:30 a.m. Tuesday, students were seated in the auditorium for an orientation and introduction to their teachers, only two of whom had shown up.

Shortly after 9, Stephenson said, one parent, Darlene Williams, warned the students to leave because of an asbestos problem. The majority of the students "charged the doors," he said, and walked out of the red-brick building.

"She created an unruly and chaotic situation," Stephenson said.

In a letter Wednesday, Stephenson told Williams that she "caused a great disruption" and warned that "if this conduct continues" he would try to bar her from school grounds.

School officials said they did not believe the building had exposed asbestos, but they said that extensive renovations are to begin after summer school ends on Aug. 10.

In an interview at yesterday's protest, Williams said she told the students to go home only because there were not enough teachers to provide instruction. "We've got more security than we've got teachers," she said, gesturing at a group of private security guards gathered outside the school doors.

Parents outside the school yesterday sided with Williams. Brenda J. Jones, 50, said her 12-year-old daughter, Antionette, "did not even want to come today because she said it's not like real school." Antionette, a seventh-grader, was in a class of about 25 students, but only three were at her age and grade level, Jones said.

Mary K. Ford, 49, said her 13-year-old daughter, Tianca Lyles, also is in a crowded class. "When you've got that many kids in the class, you can't get attention," she said.

Curry said the ideal class size for summer school is 10 to 12 students.

Both Jones and Ford said their children had told them that Stephenson was personally teaching classes because of the teacher shortage. Stephenson disputed their account.

Florence Royster and daughter Keavonni Royster, 12, join in the protest at Sousa Middle School in Southeast Washington.Brenda J. Jones says her daughter, who will be a seventh-grader, doesn't want to go to summer school at Sousa Middle "because she said it's not like real school."