Ukrainian President Volodymyr Zelensky has said that establishing the causes of the Ukraine International Airlines (UIA) plane crash in Iran is a priority for Ukraine, the Office of the President has reported.

"We will definitely find out the truth. For this, a detailed and independent investigation is carried out in accordance with international law," the press service of the office said.

Zelensky expressed his condolences to the relatives of all the dead in the crash of the Ukrainian plane near Tehran (Iran), in particular, 11 Ukrainians on board, as well as citizens of Iran, Canada, Sweden, Afghanistan and the United Kingdom.

"The morning of January 8, 2020 became a black page in the history of Ukraine and the whole world. My sincere condolences to the relatives and friends of the eleven dead citizens of Ukraine: Volodymyr Haponenko, Alexei Naumkin, Serhiy Khomenko, Kateryna Statnik, Ihor Matkov, Maria Mykytiuk, Denys Lykhny, Valeria Ovcharuk, Yulia Solohub, Olena Malakhova and Olha Kobiuk," the press service, citing the president.

According to the president, the investigation of the crash will be carried out by a commission created by the Civil Aviation Organization of the Islamic Republic of Iran. A total 45 Ukrainian specialists will join them, including from the State Aviation Service, the National Bureau of Air Accidents Investigation of Ukraine and representatives of UIA.

In addition, if necessary, representatives of the National Security and Defense Council, the Security Service of Ukraine, the State Emergency Service, the Ministry of Defense, the ministries of foreign affairs, the interior affairs and other government agencies who also arrived in Tehran can be included in the commission.

"These are the best specialists in our country who have extensive experience in examinations. They will identify and repatriate the dead Ukrainians. We expect all of them to be included in the work of the commission, in particular to deciphering the records of "black boxes [flight data recorders]," Zelensky said.

Zelensky also said that on Thursday he intends to talk on the phone with the Iranian president to enhance cooperation with the Ukrainian side to establish the truth. He also called on the international community, in particular Canada, to investigate the circumstances of the crash of the Ukrainian Boeing 737.

The head of the Ukrainian state said that Ukraine would conduct unscheduled and complete checks of UIA and other domestic airlines for airworthiness. Until all the causes of the disaster have been clarified, Ukrainian airlines have been banned from flying in the airspace of Iran and Iraq, and Ukrainian citizens are advised to refrain from visiting this region.

"Before the takeoff of the Ukrainian plane, and after it, the planes of international, including European airlines, landed and took off at Tehran's international airport. Only the United States banned flights. None of the countries prohibited their flights over Iran, but did not cancel flights before the morning plane crash," he said.

Zelensky called on Ukrainians to refrain from unverified information and manipulations until a preliminary investigation report is made public.

"Now our information space is full of numerous theories and myths regarding the tragedy... In such cases, speed can impede finding the truth. We need to wait at least for the preliminary report of the investigation commission. And I ask everyone... to refrain from manipulation, speculation, conspiracy theories, hasty categorical assessments and unverified versions. This is not a topic for hype, 'likes' in social networks, sensations and conspiracy theories. We need patience, self-possession and wisdom," the president said.