"Useful research has been carried out to find the causes of this crash and complementary investigations are also underway with precision and speed to reach a final concussion," Rouhani said in a phone call with Canadian Prime Minister Justin Trudeau on Saturday.
All 176 people on the Ukraine International Airlines (UIA) Boeing 737-800 died in the crash on Wednesday just after take-off from Imam Khomeini International Airport on a flight to Kiev.
The Iranian president said the crash was a "heartfelt and tragic" incident for Iranians and Canadians as well as all those whose citizens were on board the plane.
Rouhani stated that Iran has made its utmost efforts since the very first moments to find the reasons behind the crash and would inform the world public opinion about any further results.
He emphasized that he has given all necessary orders to relevant authorities and bodies to continue with technical and legal investigations.
"I am keen that the two countries' relations will continue in the future in order to help [improve] welfare of Iranians residing in Canada and to serve the two nations in different issues of mutual interest, including the promotion of regional peace and security," the Iranian president said.
On Saturday, Iran’s General Staff of the Armed Forces put out a statement saying the Ukrainian plane was shot down “unintentionally” due to “human error” and that those guilty would be brought to military justice.