The Covid-19 pandemic will delay the investigation into the downing of a Ukrainian international flight over Iran, after Canada asked Tehran to delay downloading data on the black boxes due to coronavirus travel restrictions.

Iran agreed in March to hand over the black boxes from Flight 752 to Ukraine or France for analysis – a move welcomed by Canada and Ukraine.

The boxes are expected to contain information about the last moments before the Ukraine International Airlines jetliner was struck by a missile and crashed shortly after taking off from Tehran airport on 8 January.

Last week, Iran contacted the countries involved to ask when they could send experts to help download the data off the black boxes, according to the Transportation Safety Board of Canada (TSB).

While stressing that the concerned countries were “anxious for the download and analysis of the recorders to proceed”, TSB president Kathy Fox said they all “provided a consistent response, indicating that travelling was impossible at this time, and likely for some time to come” due to restrictions imposed due to the pandemic.

The Iranian military has admitted that the plane was shot down due to “human error”. Of the 176 victims, 57 were Canadian citizens and 29 were permanent residents in Canada.

The TSB added that representatives or experts from the involved countries should be present when the black box data is downloaded, and that the process should therefore be postponed until “conditions improve enough to allow for safe travel”.

“We still expect Iran will carry through with its commitment to have the recorders downloaded” once conditions improved, Fox said.