The crew of the Ukrainian plane that crashed in Iran killing all 176 people on board did not make a radio call for help, investigators have said.

Iran’s civil aviation authority said pilots were trying to turn the aircraft back to the airport in Tehran when the plane went down.

They made the comments in a preliminary report a day after the devastating crash that killed three British people.

Victims came from seven countries in total and included 82 Iranians, 63 Canadians, 11 Ukrainians and all of the crew made up of 10 Swedes, four Afghans and three Germans, Ukraine foreign affairs minister Vadym Prystaiko said on Wednesday.

The investigators also said that the plane was engulfed in fire before it crashed.

A massive explosion went off as the plane hit the ground, likely because the aircraft had been fully loaded with fuel for the flight to Kyiv, Ukraine, the report said.

It also confirmed that both of the black boxes that contain data and cockpit communications from the plane had been recovered, though they had been damaged and some parts of their memory was lost.