The Iranian side is refusing to disclose to Ukraine the names of those involved in the downing of a Ukrainian passenger jet outside the Tehran Airport on January 8, 2020.

That's according to Deputy Foreign Minister Yevhen Yenin who spoke with Ukraine 24 TV channel.

Ukraine, the diplomat said, had sent requests for international legal assistance, but the responses were either significantly delayed or lacking factual information.

"We insisted that Iran open the veil off those events, at least for a narrow circle of specialists. We also proposed that a joint investigation team be set up. We talked about conducting joint investigative action. But so far the Iranian side has not responded positively to these proposals," he declared.

"Moreover, they're still refusing to give us the names of suspected persons or those in respect of whom an indictment will be soon forwarded to court. They cite military secrets. Of course, neither the closed-door nature of trial, nor the delay in cooperation with Ukrainian law enforcement contribute to stronger confidence in the investigation pursued by Iran," the deputy foreign minister said.

Read alsoUkraine, Canada's top diplomats talk next steps on PS752 downing probePS752 downing in Iran: Background

On January 8, 2020, Kyiv-bound Boeing 737 passenger jet flight PS752, operated by Ukraine International Airlines, crashed in Iran shortly after takeoff from Tehran Airport.

All 176 people on board, including 11 Ukrainian nationals – nine crew and two passengers – were killed. Among victims are also citizens of Iran, Canada, Sweden, Afghanistan, Germany, and the UK.

Iranian President Hassan Rouhani admitted that the Ukrainian liner had been shot down as a result of an unintentional "human error," and promised to bring those responsible to justice.

On June 9, media reports said Iran had accused six persons in the PS752 downing case.

On July 20, the flight recorders were delivered to Paris and decrypted on July 21.

On July 24, it was reported that data from the black boxes had confirmed external interference with the aircraft's operation.

On October 23, Ukrainian Deputy Foreign Minister Yevhen Yenin said Iran would pay compensation to the relatives of victims of the UIA flight PS752 crash, but the process might last up to two years.

On December 9, however, Yenin said that Iran had withdrawn the offer to handle the payments to the families of those killed in the UIA plane crash.

In the middle of December, Canada expressed its position on the Iranian investigation into the downing of the Ukrainian plane, saying it is not credible.

On December 22, the Iranian news agency Tasnim reported that Iranian investigators, during a video conference, had provided representatives of other countries whose citizens were victims of the crash with a technical report on the UIA downing.

On December 23, Yenin said Ukraine had not received the report.

On December 24, Foreign Minister Dmytro Kuleba expressed concern that Iran was delaying the negotiation process on the case of the downed Ukraine International Airlines plane. He noted that Ukraine had not received a technical report from Iran on the plane downed almost a year ago.

On December 30, Iranian cabinet members reportedly agreed at a session to allocate US$150,000 or its equivalent in euros to each family of the victims of the Ukrainian plane crash in January 2020.

On January 7, 2021, Rouhani said all those responsible for the downing of the plane would be brought to justice.

The Canadian government and security agencies are reviewing an audio recording in which a man – identified by sources as Iran's foreign affairs minister – discusses the possibility that the destruction of Flight PS752 was an intentional act.

On Iranian Military Prosecutor's Office has completed a pre-trial investigation into the incident, Iranian media reported February 21.