After the death of Iran' President Ebrahim Raisi, Foreign Minister Hossein Amir-Abdollahian and eight others on Monday, Iranian state media has reported that the helicopter crash was caused due to a "technical failure".

President Raisi and the country's foreign minister had visited the Azerbaijan border on Sunday to inaugurate a new dam project. On their return, the helicopter carrying them and other top officials crashed in the mountainous terrain in northwest Iran.

The crash, which occurred on Sunday night, resulted in a mass search operation across the northwestern region. Almost 12 hours after the crash, rescue teams found the wreckage for the chopper crash and declared that there were no survivors.

Following the crash and the death of the two most influential leaders in Iran, officials hit out at the US and its sanctions on Tehran for the crash.

However, the US has denied having any role in the crash. Defence Secretary Llyod Austin confirmed that Washington did not play a role in the death of the President and Foreign Minister.

Along with the US, eyes were also on Israel owing to the recent drone attacks between the countries. However, Israeli officials have also ruled out any involvement in this crash.

As per the latest reports by Iranian state media, the crash was caused by a technical failure in the helicopter's engines.

The helicopter - a Bell 212 aircraft - had been developed by for the Canadian military in the late 1940s. The model was reportedly designed by the US.

Following the death of President Raisi, Foreign Minister Amir-Abdollhian and eight others, Iran has declared a five day mourning period from Tuesday to Thursday. Due to the president's sudden death, first vice president Mohammed Mokhber was elevated to acting president for the next 50 days.