The black box of the Boeing aircraft, with all 157 people crashed on board, is sent abroad for analysis, but no land was selected. Families arrived at the scene of the disaster.
In an interview with The Associated Press, Asrat Begashaw said the airline has "a number of options" for the data and voice recordings of the last moments of the flight. "What we can say is that we do not have the opportunity to investigate here in Ethiopia," he said.
The Boeing 737 Max 8 crashed shortly after take-off on Sunday and killed all 157 people on board. The disaster is the second with a Max 8 aircraft in just five months.
While some aviation experts have warned against drawing conclusions until further information about the recent crash is known, much of the world, including the entire European Union, has relocated the Boeing jetliner or banished it from its airspace.
This leaves the United States one of the few remaining operators of the aircraft.
"Similar causes could have contributed to both events," said the European regulator, citing the plunge of Lion Air in Indonesia, which killed 189 people last year.
British regulators pointed to potential problems with an allegedly damaged flight data recorder, which could hinder the retrieval of information.
Some aviation experts have warned that it can take months to find answers.
Asrat, spokesman for the Ethiopian Airlines, told the AP that the remains of the victims so far recovered are in freezers, but the forensic DNA work for identification has not yet begun.
The dead came from 35 countries.
More devastated families arrived at the crash site on Wednesday. Some were supported by relatives and lamentations.
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