Some suspects have been arrested for firing the missile that brought down a passenger plane shortly after takeoff in Iraq’s main airport.

The judiciary spokesperson, Iran, Gholamhossein Esmali, said “extensive investigation has taken place and some individuals are arrested,” on Tuesday. He did not give further information on the arrest.

About 176 passengers were killed on Wednesday morning, en route to Kyiv from Tehran.

The plane was brought down a couple of hours after Iran had launched missile attacks on U.S. targets in Iraq. The attack was in retaliation for the assassination of Iranian Military Chief Qasem Soleimani in Baghdad on January 3.

Initially, Iran denied having any involvement in the crash blaming it on technical difficulties. “The plane caught fire due to a technical defect and this resulted in a crash,” the transport minister of Iran Mohammed Eslami had said on Thursday.

Nevertheless, further investigations proved that the missile attack brought the plane down.

Canadian Prime Minister Justin Trudeau, on Thursday stated that “evidence indicates that the plane was shot down by an Iranian surface-to-air missile.”

Iran on Saturday, admitted that indeed the plane that was brought down was due to a missile fired at it by its officials ‘mistakenly’. This acknowledgement led to protests against senior officials which included Supreme Leader Ayatollah Ali Khamenei.

According to Aljazeera, Iranian President Hassan Rouhani on Tuesday in a televised address promised that a thorough investigation would be carried out.

He said, “for our people, it is very important in this incident that whoever was at fault or negligent at any level faces justice, anyone who should be punished must be punished.”

He commended the government’s admission of shooting down the plane, saying it is a “first good step.”

He said such occurrences will not happen again and that his government was “accountable to Iranian and other nations who lost lives in the plane crash.”