White House spokesman John Kirby has said the US has seen “early indications” that Russia may have been responsible for the downing of the Azerbaijan Airlines plane that crashed on 25 December, killing 38 people.
Mr Kirby did not elaborate further, but told reporters the US had offered assistance to the investigation into the crash.
The plane is thought to have come under fire from Russian air defence systems as it tried to land in Chechnya before being diverted across the Caspian Sea to Kazakhstan, where it crashed.
The Kremlin has refused to comment, but the head of Russia’s civil aviation agency said the situation in Chechnya was “very complicated” due to Ukrainian drone strikes on the region.
Mr Kirby said the indications the US had seen went beyond widely circulated photos of the damaged plane, the Washington Post reported.
Aviation experts and others in Azerbaijan believe the plane’s GPS systems were affected by electronic jamming and it was then damaged by shrapnel from Russian air-defence missile blasts.
Azerbaijan has not accused Russia, but the country’s transport minister said the plane was subject to “external interference” and damaged inside and out as it tried to land.
“All [the survivors] without exception stated they heard three blast sounds when the aircraft was above Grozny,” said Rashad Nabiyev.
Mr Nabiyev said investigators would now examine “what kind of weapon, or rather what kind of rocket was used.”
However, pro-government MP Rasim Musabekov was clear: “The plane was shot down over Russian territory, in the skies above Grozny. Denying this is impossible.”
He told AFP news agency the plane had been damaged and the pilot had asked to make an emergency landing in Grozny. Instead of being directed to nearby airports, he said it was “sent far away” across the Caspian Sea without GPS.
Flight attendant Zulfuqar Asadov described the moments when the plane was hit by “some kind of external strike” over Chechnya.
“The impact of it caused panic inside. We tried to calm them down, to get them seated. At that moment, there was another strike, and my arm was injured.”
The pilots of the Embraer 190 plane are credited with saving 29 of those on board by managing to land part of the plane, despite themselves being killed in the crash.
The Kremlin has refused to comment on the increasing number of reports that the Azerbaijan Airlines plane was hit by Russian air defence.
“An investigation into this aviation incident is underway and until the conclusions are made as a result of the investigation, we do not consider ourselves entitled to give any assessments,” said spokesman Dmitry Peskov.
Kazakh authorities have been treating the injured and working closely with Azerbaijan on the investigation.
Reports in Baku suggest both Russia and Kazakhstan have proposed having a committee from the Commonwealth of Independent States (CIS) – a regional organisation dominated by Russia – investigate the crash, but Azerbaijan has instead demanded an international inquiry.
