A Ukrainian passenger plane that crashed outside Tehran earlier this week had flown close to a sensitive military site and was brought down due to human error, a top Iranian armed forces official said on Saturday.
The news was confirmed by General Staff of the Armed Forces of the Islamic Republic of Iran, reports Press TV.
A statement carried by Iranian state TV said that it had done so after the plane flew close to a sensitive site belonging to Iran's Revolutionary Guards, the BBC reported.
Those responsible would be held accountable, the statement said.
Iran had previously rejected suggestions that one of its missiles brought down the plane the Kiev-bound Ukraine International Airlines (UIA) flight PS75, which crashed shortly after taking off from Tehran, killing all the 176 people on board.
Saturday's development comes after Canadian prime Minister Justin Trudeau said on Thursday citing intelligence reports that the Ukrainian airliner was shot down by an Iranian missile.
Sixty-three Canadians were aboard.
Trudeau's remark followed US media reports that said the airliner was was mistakenly shot down by Iran.
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.
But on Friday, Ali Rabiei, spokesman for the Iranian administration, denied the claims, saying "these reports are psychological warfare against Iran ... all those countries whose citizens were aboard the plane can send representatives and we urge Boeing to send its representative to join the process of investigating the black box".
The crash came just hours after Iran carried out missile strikes on two airbases housing US forces in Iraq in retaliation to the death of Iranian Major General Qasem Soleimani, who was killed in an American drone attack on January 3 in Baghdad.