The two flight data recorders have been recovered from a Ukrainian passenger plane which crashed in Iran, killing all 176 people on board.
Ukraine will soon send a team of experts to Iran to investigate the circumstances of the incident.
Meanwhile, Ukrainian president Volodymyr Zelensky has warned against speculation and coming up with unconfirmed theories about the crash.
Zelensky has ordered the creation of a crisis team, managed by the country's national security agency.
The flight from Tehran to Kiev operated by Ukraine International Airlines crashed shortly after takeoff from Tehran airport in the early hours of Wednesday.
The Ukrainian Embassy in Tehran initially said the plane went down "due to an engine problem".
5 dead, more than 80 missing after Philippine ferry fire
US military says it struck vessel in Caribbean, killing 3
At least 14 killed in explosion at weapons depot in Syria
US hits five Iranian oil tankers after attack on Navy ships
UK gives air traffic provider a week to probe outage that halted flights
Serbia's President Vucic dissolves parliament, calls snap elections
With large crowds attending, Norway lays King Harald to rest
Jordan intercepts 18 Iranian ballistic missiles
