Russia started on Friday to examine the black box of the Su-24 fighter jet that was downed by Turkish air force in Syria in November, revealing more facts about the incident.

Russia started on Friday to examine the black box of the Su-24 fighter jet that was downed by Turkish air force in Syria in November, revealing more facts about the incident.

"We have sufficient evidence that proves that the Russian aircraft did not violate Turkish airspace," said Sergey Dronov, deputy commander of the Russian Air and Space Forces, adding that the downed plane had been flying in Syrian airspace 5.5 kilometers (around three miles) from the border with Turkey.

The Russian military have invited experts from 14 nations to work on the flight recorder of the Russian Su-24 bomber, but only two of them accepted their invitations, the Defense Ministry reported, before unsealing the device.

The experts who agreed to participate in the study of the flight recorder, which is to provide further evidence into the highly controversial incident, come from the UK and China, Dronov told the media.

Turkey shot down the Russian warplane on November 24 as it was conducting an anti-terrorist mission in a region close to the Turkish border. Ankara said it used force in response to a 17-second violation of its airspace and was fully justified in doing so.

Moscow denied that any violation happened, a statement that the flight recorder may help to confirm. The device was recovered by Syrian and Russian troops shortly after the incident and transported to Russia for investigation. Moscow pledged that the study of the flight recorder would be carried out with maximum transparency to avoid any shadow of doubt that it had been tampered with.

State television broadcast the opening of the orange device on state television as military officials insisted it was intact. A preliminary report into the findings is expected Monday.