Rescuers work at the air crash site of a Boeing 737 Ukrainian passenger plane in Parand district, southern Tehran, Iran, on Jan. 8, 2020. (Xinhua/Ahmad Halabisaz)

Iran has admitted that it "unintentionally" shot down a Ukrainian passenger airplane, citing "human error," Iran state TV reported on Saturday.

A Boeing 737 plane operated by Ukraine International Airlines crashed on Wednesday shortly after takeoff from Tehran's main airport, killing all 176 people on board.

A statement from the Iranian military said the flight had left Imam Khomeini International Airport and was close to a "sensitive military site" of the Islamic Revolutionary Guard Corps when it was shot down.

Iranian foreign minister Zarif said, "Human error at a time of crisis caused by US adventurism led to disaster," in a tweet on Saturday. 

"Our profound regrets, apologies and condolences to our people, to the families of victims, and to other affected nations," the foreign minister wrote. 

The plane was carrying 167 passengers and nine crew members from several countries, including 82 Iranians, 57 Canadians and 11 Ukrainians, according to officials.

The Iranian armed forces also extended their condolences to the families of the victims and apologized for the error.  

Iran will make sure that reforms are made at the force level so that such mistakes do not happen again, the military statement said.  

The military also ordered relevant departments to give detailed explanations to the people as soon as possible.