The Ukrainian Embassy in Iran initially blamed last week's plane crash in Tehran on engine failure in an attempt to gain access to the crash site, a Ukrainian security official told Reuters on Monday.
"If we had said straight away that they had shot it down, I am not sure they would have let us go to the wreckage at all," Oleksiy Danylov, secretary of Ukraine's national security and defence council, said.
Danilov said that a senior investigator is set to visit Ukraine in the coming days to establish whether local laboratories are suitable for decoding the black boxes.
The Ukrainian Embassy initially issued a statement pointing to engine failure as the cause of the crash on Wednesday. However, the statement was soon replaced by another one stating that the reasons for the deadly incident remained unknown.
On Wednesday, a Ukrainian Airlines passenger plane took off from Tehran Airport but crashed soon afterwards killing all 176 people on board.
Days later, Iran admitted that the plane was mistakenly shot down by its military.
France's Bureau of Enquiry and Analysis for Civil Aviation Safety said on Saturday that the black boxes of the plane that crashed in Iran will be deciphered in Ukraine, with French experts taking part in the technical work.