(CNN) Secretary of State Mike Pompeo said Friday that the US believes it's "likely" Iran shot down a Ukrainian jetliner that crashed near Iran's capital Tehran earlier this week, killing all 176 people on board the Boeing 737-800.
"We do believe it's likely that plane was shot down by a Iranian missile," Pompeo said at the White House.
Pompeo said when a final determination is made, "we and the world will take appropriate response."
Pompeo's assessment comes after the leaders of Canada and Britain said that they have intelligence that the Ukrainian airliner was shot down by an Iranian surface-to-air missile.
CNN obtained video on Thursday that appears to show a missile being fired into the Tehran sky and striking an object, around the same time that a Ukrainian plane crashed just after taking off from the city's airport.
CNN reported earlier Thursday that the US increasingly believes Iran mistakenly shot down the airliner, according to multiple US officials. The working theory is based on continuing analysis of data from satellites, radar and electronic data collected routinely by US military and intelligence.
A US official familiar with the intelligence said the plane was shot down by two Russian made SA-15 surface to air missiles. The US saw Iranian radar signals lock onto the jetliner, before it was shot down.