Pro-Russian separatists have admitted to downing the Malaysia Airlines flight over Ukraine, the Security Service of Ukraine (SBU) said Friday.
The SBU said it had learnt this based on the intercepted telephone calls between Russian military intelligence officers and the rebels.
According to the SBU, Igor Bezler, a Russian military intelligence officer, telephoned a Russian security officer, Vasili Geranin, 20 minutes after the plane crash Thursday.
"We have just shot down a plane. Group Minera. It fell down beyond Yenakievo (Donetsk region)," the Kyiv Post quoted Bezler as as saying.
Bezler is also a leading commander of the self-proclaimed Donetsk People's Republic.
Read: Ukraine rebels' posts spoke of downing 'bird'
The second intercepted conversation released by the SBU was apparently between two militants nicknamed "Major" and "Greek" immediately upon the inspection of the crash site.
"It's 100% a passenger aircraft," Major is recorded as saying, as he admitted to seeing no weapons on site.
"Absolutely nothing. Civilian items, medicinal stuff, towels, toilet paper."
Read: Who shot down the Malaysia airliner?
In the third intercepted conversation, Cossack commander Nikolay Kozitsin tells an unidentified militant that the MH17 could have been carrying spies. Otherwise, it would have no business flying in that area.
Meanwhile, an initial review of the US intelligence too suggested that pro-Russian separatists likely shot down a the airliner. However, Washington is still examining the evidence, a US official said Friday.
"There are indications (the separatists downed the plane) but there's no final conclusion," the US official, who spoke on condition of anonymity, told AFP.
Full coverage: MH17 goes down