The National Transportation Safety Board (NTSB) released an official statement on Thursday saying it received formal notification from Iran to join the investigation into the Ukraine Boeing 737-800 crash and designated an accredited representative to the investigation.
The NTSB noted that Iran's civil aviation agency is leading the probe.
"Iran's AAIB is the lead investigative agency and questions regarding the progress of the investigation should be directed there", the statement said.
UPDATE to NTSB Statement on Ukraine International Airlines flight PS752 Crash Investigation pic.twitter.com/A6HPOl5Ow8— NTSB_Newsroom (@NTSB_Newsroom) January 10, 2020
Earlier in the day, the Canadian Transportation Safety Board said it was making arrangements to visit the crash site of the Ukranian Boeing.
Spokesman for the Iranian Foreign Ministry Ali Rabiei said that his country welcomed the participation of other countries whose citizens died in the accident in the probe, but asked not to spread speculations about the causes of the crash. The Iranian Foreign Ministry also indicated that it would keep the black boxes in Iran but allow Canadian officials access to the crash site. 63 Canadian nationals died in the accident.
Both UK's Prime Minister Boris Johnson and Canadian premier Justin Trudeau said that there was intelligence information indicating that the Ukrainian jet was unintentionally shot down by an Iranian surface-to-air missile. Trudeau, however, noted that it was too early to apportion blame on anybody or draw any conclusions.
The Ukrainian aircraft suffered a crash on early Wednesday morning just minutes after take-off from Tehran's Imam Khomeini International Airport, killing 167 passengers and nine crew members on board. Most of them were Iranians and Canadians (82 and 63 respectively), as well as 10 Swedes, four Afghans, three Germans, and three UK citizens. The plane was bound for Kiev.