Russia's defence officials said on Friday that the black box of the Russian Su-24 jet that was downed at the Turkey-Syria border last month was damaged.

The ministry, however, said that special equipment can be used to decipher the flight recorder data and that the findings will be shared on 21 December, according to TASS news agency. 

Some of the chips recovered from the black box were 'completely damaged', Russian agency Sputnik News reported. 

Russian media provided live coverage of the opening of the black box before journalists in Moscow on Friday. 

Russia had invited experts from 14 nations to join the investigation of the black box in order to ensure 'trasnperency'. However, only China and Britain have joined the probe. 

"In order to ensure maximal transparency and openness, we addressed foreign experts from 14 countries with an invitation to take part in the work (investigation) as observers. However, many specialists refused to participate in the investigation citing various reasons, excluding only Mr Liu Chang Wei from China and Mr Jonathan Gillespie from the United Kingdom," Deputy Commander of Russian Aerospace Defense Forces Sergey Dronov said. 

The downing of the Russian jet by Turkey, which claimed the pilot had ignored warnings by Turkish jets after he entered Turkey's airspace, led to a diplomatic breakdown between the two countries. 

Russia has maintained that its jet did not violate the Turkish airspace. 

Russian President Vladimir Putin had said during his media conference on Thursday that he did not see prospects of ties improving with Turkey, calling the jet downing 'an enemy act'. 

Analysis and processing of the flight data will be done on Saturday, the Russian news agency said.