Officials are trying to locate a car that raced through a suburban Rockville area early Monday moments after a powerful bomb blast demolished portions of a home owned by a prominent pro-Israel lobbyist, Montgomery County police said yesterday.

The officials were reacting to more than three dozen telephone calls they received in connection with the bombing at 3:20 a.m. Monday morning of Morris J. Amitay home, located at 4712 Sunflower Dr. in the Flower Valley section of the county.

The callers have supplied police with several incomplete license plate numbers, police said. The spokesman declined to identify the jurisdiction in which the license plates were issued, but said the plates were from "the Washington area."

Police have identified a "likely, though not definite" escape route for the car driven by the bomber or bombers based on the reports phoned in by witnesses, according to county police spokesman Philip B. Caswell.

The route taken by the person who planted the bomb is important to police because it may help lead them to other witnesses who may have additional information to contribute to the investigation, Caswell said.

Police said that no person or group has claimed responsibility for the blast, which caused at least $50,000 damage to the Amitay's $100,000 home.

Charles Stanfill, who heads the Treasury Department's Alcohol, Tobacco, and Firearms Division's Hyattsville office, which is coordinating the investigation, said yesterday that "no concrete leads" had been developed.

Stanfill added that "we are looking at cars that don't belong in the (Amitay) neighborhood," a subdivision of winding streets and attractive, two-story brick homes.

Sources close to the investigation said that dynamite was most probably used in the blast, which shattered windows within a five-block radius of the home, lifting roofs and shingles on nearby residences. Investigators continued yesterday to study residue of the explosive device found at the site in an effort to identify it, the sources said.

The bomb, which was placed below a second story bedroom window, was detonated from a distance by means of a 400-foot piece of household electrical cord. The explosion was so powerful that it blew splinters and fragments of glass across the bedroom - where the children were sleeping - into the opposite wall, sources said.

A ceiling section fell on the Amitay's 9-year-old daughter, but she was not injured, the sources added.

Amitay, 41, is executive director of the American Israel Public Affairs Committee, the only domestic group registered to lobby on Capitol Hill on behalf of pro-Israel causes.

Because of his position, Amitay is highly visible as a pro-Israel spokesman, according to congressional sources. These people have speculated that the bombing might have been committed by someone opposed to Israel itself rather than directed at Amitay for personal reasons.

Federal and local officials, however, have said that so far they have "no information whatever" linking the bombing to any political or terrorist group.

As for a motive in the violent incident, Cpl. Caswell of the Montgomery County police discounted the idea that the bombing was a "warning" of some kind. "If they wanted to warn him they could have planted the bomb by the garage," on the other side of the house, and not under the bedroom window, he said.

The route police believe may have been taken by the fleeing bomber runs from the intersection of Sunflower Drive and Bitterroot Way, where the Amitay home is located, south of Bitterroot for one block, east on Flower Valley Drive for one block, and then south on Columbine Way for another block, Caswell said.

At that point Columbine intersects with Norbeck Drive, a major thoroughfare in the area. Police believe the vehicle may have them turned right onto Norbeck, and traveled southwest for half a mile to Bel Pre Road, where it turned left and continued traveling away from the bomb site at a "high rate of speed." Caswell said.