SANTO DOMINGO, Dominican Republic (AP) _ The U.S. Navy is bringing in sophisticated sonar equipment to help find the flight data recorders of a jetliner that crashed into the Caribbean Sea.

The equipment is capable of picking up signals from the plane's ``black boxes,'' believed to have sunk when the Boeing 757 crashed off the Dominican Republic's north coast resort of Puerto Plata last Tuesday, killing 189 people.

A ship carrying the equipment left Miami late Saturday and was to arrive in Puerto Plata by Tuesday, U.S. Navy Lt. Greg Geisen said in Washington on Sunday.

The Navy plans to map the topography of the seafloor near the crash site and narrow down the search area, where waters are at least 4,000 feet deep.

The listening device then will be lowered underwater by cables. A remote-control submarine could be used to recover the data recorders and other objects.

Flight 301, carrying mostly German tourists to Berlin and Frankfurt, Germany, crashed shortly after takeoff from Puerto Plata on Tuesday. The Turkish-owned plane had been leased to Alas Nacionales, a Dominican airline.

The remains of 72 people and hundreds of small pieces of debris were recovered but provided few clues for investigators.

``We're biding our time. Until the new equipment arrives ... there won't be anything new'' on the probe, said Eugenio Cabral, director of Dominican civil defense.

In Santo Domingo, German and Dominican forensic scientists were working to identify victims in a morgue at the National Forensic Pathology Institute. They made use of passports, wallet identifications and other documents recovered at the crash site.

Results of the forensic work weren't expected for several days. However, none of the bodies had burns that could suggest a fire or explosion before the plane crashed, said institute director Dr. Vertilio Cornielle.