Nine RAF personnel and one soldier are missing, believed dead, in the largest single loss of British life in Iraq since military action began.
Flags were flown at half-mast at RAF Lyneham in Wiltshire
They died after a British Hercules plane came down on Sunday evening 25 miles (40km) north-west of Baghdad.
Al-Jazeera has aired a video reported to have come from insurgents who claim they shot down the plane, showing burning wreckage on the ground.
The MoD has refused to comment on the authenticity of the video.
Wreckage from the C-130 plane, which is known for its reliability, was spread over a wide area, after crashing in fine conditions at 1725 local time (1425 GMT).
Australian airman Flt Lt Paul Pardoel, 35, of Victoria State, is the only one of the 10 victims to be named so far.
The father-of-three, who had lived in the UK for three years, is thought to be the first Australian serving in Iraq to die.
His mother, Margaret, said her son was planning to retire and return to Australia in July.
"He said to me one night when he phoned - 'Mum there's nowhere to hide here, it's just so dangerous, there's nowhere to hide'," she told the Australian Broadcasting Corporation.
A statement from RAF Lyneham in Wiltshire, where the Hercules was based, said the families of those believed dead had been contacted.
Their names are expected to be released on Tuesday.
The video aired by al-Jazeera shows two rockets being fired, before it cuts to plane wreckage on the ground.
It is unclear if the wreckage shown in the video is of a Hercules C-130
A spokesman for the news channel said the video came from a faction of the 1920 Revolution Brigade, a group named after the uprising against the British after World War I.
The footage did not show missiles hitting a plane, and it was not certain that the wreckage was that of a Hercules C-130.
Air Chief Marshal Sir Jock Stirrup, the RAF's chief of air staff, said he has "no evidence at all" to dispute or confirm the video's claims.
"We have people on the ground sifting through the aircraft wreckage looking for clues," he said.
Earlier, Mr Hoon said coalition forces had secured the crash site and had started recovering the victims' bodies.
"We are aware of reports that the aircraft may have been shot down but we are not in a position to come to any conclusions until the investigation is complete," he said.
Foreign Secretary Jack Straw sent "deepest condolences" to the families of the servicemen on behalf of the House of Commons.
Tributes have been left at the plane's base in Wiltshire
The Hercules had been en route from Baghdad to Balad, which houses one of the largest US air bases in Iraq.
Balad is home to about 25,000 US troops and has been the frequent target of mortar attacks by Iraqi insurgents.
There are usually no British troops based in Balad and the purpose of the flight was unclear.
Some newspapers have speculated that the plane was carrying Special Air Service (SAS) personnel, but the MoD insists the flight was routine.
Well-wishers have been leaving flowers at the Wiltshire base since news of the crash broke on Sunday.
The MoD has a phone number for concerned relatives to call: 08457 800 900