US officials say they believe the Ukrainian International Airlines Boeing 737-800 was hit by a missile, CBS said.
In separate reports, CBS News and Newsweek said US and Iraqi intelligence officials were confident the Ukrainian plane was brought down by a missile fired by Iran, reported BBC.
CBS published a brief report on Twitter, saying the officials were confident the plane was shot down.
It said this information was based on US intelligence, which sources said picked up signals of a radar being turned on. US satellites also reportedly detected two missile launches shortly before the Ukrainian plane exploded.
Meanwhile, Newsweek quoted US and Iraqi officials as saying they believed the aircraft was hit by a Russia-built Tor M-1 surface-to-air missile system, known as Gauntlet by Nato.
Two Pentagon officials assessed that the incident was accidental, Newsweek added.
It quoted sources as saying that Iran's anti-aircraft systems were probably active following its attacks on the US airbases.
Ukraine earlier said it was examining whether a missile strike brought down the aircraft - but Iran ruled this out, BBC reported.
The crash came just hours after Iran carried out missile strikes on two airbases housing US forces in Iraq.
CBS News quoted US intelligence sources as saying a satellite detected infrared "blips" of two missile launches, followed by another blip of an explosion.
Meanwhile, Newsweek quoted a Pentagon and senior US intelligence officials, as well as an Iraqi intelligence official, as saying they believed the Ukrainian plane was hit by a Russian-made Tor missile.
US President Donald Trump said on Thursday that "I have my suspicions" over the plane. "Somebody could have made a mistake," he said.
Amid tensions heightened by the US killing of top Iranian general Qasem Soleimani on 3 January, Iran has said it will not hand over the recovered black box flight recorders to Boeing, the plane's manufacturer, or to the US.
Under global aviation rules Iran has the right to lead the investigation, but manufacturers are typically involved.
( With inputs from IANS )