Two 4-year-old Maryland children have been hospitalized in separate incidents while playing at local day care centers in the state, local police and fire officials said.

In once incident, a Mitchellville boy was listed in critical condition at Children's Hospital yesterday after being found Monday afternoon entangled in a rope on a swing set at a day care center in Lanham. Police said they had no details on the incident.

According to a Prince George's County Police Department spokeswoman, police officials are "quite certain it was accidental."

But she added that the case is still under investigation by police and county health department officials.

The child, Brian V. Sanders, who was in the intensive care unit at Children's Hospital, was undergoing tests, including brain scans, according to his mother.

Officials refused to comment yesterday on whether the child was supervised at the time of the injury, which occurred at the Willow Tree Day Care Center in Lanham. The center's director declined to comment.

Yesterday, in the second incident, a Howard County girl was pulled from the swimming pool at the day camp she attended after she swallowed water and slipped beneath the surface, fire officials said.

Cmdr. Donald Howell said that Joann Theiss of Fulton-Highland was discovered at the bottom of the pool at the Circle D Farm in Lisbon. Estimates of how long she had been underwater varied from 35 seconds to four minutes, Howell said.

The girl was in stable condition at the intensive care unit at Montgomery County General Hospital, where she was taken for observation.

Howell said the afternoon incident was the eighth drowning or near-drowning reported in the county this year, a statistic that he described as "uncanny in a county this size."

Of the eight incidents, three resulted in death, he said, including a man who drowned in a pond in Savage last weekend.

Timothy Dowd, the day camp's owner and a former professional firefighter, said Joann Theiss was never in danger of drowning because the pool was attended by three lifeguards, who immediately removed her from the water and began administering mouth-to-mouth resuscitation.

"She just took in a little water and panicked, that's all," he said. "The lifeguards did exactly what they were supposed to."