Two young sisters who were pulled unconscious from an icy neighborhood pond in Montgomery County were pronounced dead early yesterday after rescuers failed to revive them, according to police.

The two girls, Michelle Luna, 11, and Rachel Luna, 9, were pulled from Valley Mill Pond about 11:30 p.m. Sunday by a team of divers from the county Fire and Rescue Department.

Both girls died early yesterday morning at Children's Hospital of complications from being submerged for an undetermined length of time in the freezing waters, authorities said. Autopsies are scheduled to be performed by the D.C. Medical Examiner's Office.

The girls' father, Fernando Luna, frantically began searching their neighborhood Sunday afternoon when his daughters failed to return from playing outside, according to neighbors. Valley Mill Pond is in the Snowden Mill neighborhood of Silver Spring, which is between New Hampshire Avenue and Route 29. Officials at the Maryland National Capital Park and Planning Commission, which owns the pond, said signs were posted last month warning residents to stay off, but apparently those signs were no longer up when the drownings occurred.

It was not clear yesterday what enticed the girls to go to the pond or what they did when they got there.

Yesterday, the Luna parents grieved for their only children, according to a relative. Playmates and other friends talked quietly about the "very smart girls" and their reluctance to hang out at "Girl Scouts' Pond," the nickname used in the neighborhood.

"Michelle was an A student," said one boy, sitting on his bicycle among a group of about five friends outside the Luna family's house on Serpentine Way. The boy said Michelle, a sixth-grader, "was very quiet."

James Manis, 14, said Michelle "was never the type of person to go near that pond. She had been told repeatedly by her parents not to go there."

For most neighborhood children, the quarter-acre pond is a popular gathering place.

"I ice-skated on the pond last year," said 14-year-old Mike Weisbord. "The ice gets very thick." Other children said they had played ice hockey on the pond and ridden bikes across it.

According to Montgomery County police, Fernando Luna last saw his daughters about 1 p.m., when they left their brick house to play outside and visit a friend.

The Lunas were unavailable for comment yesterday, but a woman who identified herself as a relative said, "The kids had permission to go out and play."

She said the father became worried about 2 p.m. when he could not find the girls.

Weisbord said he saw Fernando Luna looking through clumps of pine trees late Sunday afternoon. "He was on the verge of tears," Weisbord said. The father apparently searched the neighborhood alone until about 8:30 p.m., when the girls' mother, Mercedes Luna, called police, said Sgt. Harry Geehreng.

County police, joined by Park Police and a Maryland State Police helicopter crew, scoured the area for the girls. At 11:10 p.m., a team of six divers was called to the scene after police found footprints leading to a large hole in the ice-covered pond, officials said.

Within 10 minutes, divers pulled one girl from six feet of water, a fire official said. The second girl was removed five minutes later from the same area, the official said.

Fire officials tried to resuscitate them, an official said. Michelle was pronounced dead at 1:57 a.m. Her sister, a second-grader at Page William Tyler Elementary School, died at 3:57 a.m., authorities said.

Yesterday, several neighborhood children and adults complained that no warning signs were evident at the pond.

But park officials said the pond is off-limits for ice skating and other winter activities. Michelle Rosenfeld, staff attorney for the park commission, said an inspection in December found three warning signs posted around the pond. Yesterday however, Rosenfeld said, park workers could find no signs in the area.

Rosenfeld said park officials planned to install new signs this week. She said park authorities seldom encounter unauthorized ice skating on park-owned ponds. But one park official said the agency receives "quite a few calls" each winter about illegal ice skating on a pond in the Kemp Mill neighborhood.

Rosenfeld said the park commission, as a government agency, is exempt from a county law that requires private property owners to fence in ponds or swimming pools. Rosenfeld said she does not believe the park commission can be held liable for the drownings.