"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.
The statement added that "by pursuing fundamental reforms in operational processes at the armed forces' level, we will make it impossible to repeat such errors."
Later on Saturday, Head of the Aerospace Division of the Islamic Revolution Guards Corps (IRGC) General Amir-Ali Hajizadeh accepted full responsibility for the downing of the Ukraine aircraft and said he had “wished he could die” after being informed of the matter on the same day the crash took place.
Hajizadeh said he had notified relevant authorities immediately but that public announcement of the matter was pending an investigation of Iran’s General Staff of the Armed Forces as required by existing procedures.
Elsewhere in his remarks, the Iranian president warned that meddlesome measures by the United States have endangered security in the sensitive Middle East and called for collective efforts to restore full stability and security to the region.
"The solution to [restoration of] regional stability and security as well as nations' peace is that all act based on law and we believe that security in this region will be established only through cooperation among all regional countries," Rouhani pointed out.
Canada ready to cooperate with Iran on plane crash: Trudeau
The Canadian prime minister, for his part, stressed the importance of determining the exact causes of the incident and said Ottawa is ready to cooperate with Tehran in this regard.
He expressed hope the two countries would hold more talks about issues that have impacts on regional security.
Iran-Ukraine technical cooperation will continue: Rouhani
In a phone call with his Ukrainian counterpart Volodymyr Zelensky, the Iranian president said Tehran and Kiev would continue technical cooperation to determine the causes of the incident with seriousness and added that those responsible for the incident would be brought to justice.
Rouhani noted Iran is fully committed to its legal commitments in this regard.
Zelensky, for his part, hailed Iran’s law-abiding attitude and effective cooperation over the issue.
Iran's Foreign Ministry sets up working group: Spokesman
Iranian Foreign Ministry Spokesman Abbas Mousavi said on Saturday a special working group has been set up at the ministry to manage the consular affairs of the bereaved families of the victims of the plane crash.
He added that necessary orders have been given to all the Islamic Republic's political and consular representatives and airport offices to meet the requests related to the incident.