A handout picture provided by the Iranian presidency shows the Islamic republic's President Hassan Rouhani chairing a cabinet…
A handout picture provided by the Iranian presidency shows the Islamic republic's President Hassan Rouhani chairing a cabinet meeting in Tehran, Jan. 15, 2020.

Iranian President Hassan Rouhani called for "national unity" Wednesday after an eruption of protests over Iran's downing of a Ukrainian International Airlines plane.

Iran initially said mechanical problems caused the commercial jetliner to go down, before admitting days later that Iranian military personnel mistakenly shot down the plane, killing all 176 people on board.

The revelation sparked days of protests in Iran as people expressed their anger at the country's leaders.

FILE - Anti-government protesters attend a demonstration blaming the government for the delayed announcement of the unintentional downing of a Ukrainian plane last week, at the Tehran University campus in Tehran, Iran, Jan. 14, 2020.

In an address broadcast live on state television, Rouhani said "if there was a delay" by the military to disclose information about the disaster, "let them apologize."

Rouhani also demanded a full explanation of the catastrophe and cited the need for changes to how the Iranian government runs the country.

Rouhani has called on elections officials to refrain from banning potential political candidates from seeking office in the Feb. 21 general election. All candidates are currently vetted by a constitutional monitor to determine their loyalty to the country.

"The people are our masters and we are its servants," Rouhani said after a cabinet meeting. "The servant must address the master with modesty, precision and honesty."

Iranian Foreign Minister Mohammad Javad Zarif also addressed the recent protests Wednesday.

"The last few nights we've had people in the streets of Tehran demonstrating against the fact that they were lied to for a couple of days," he said. "This was a very serious situation. We believe that it is, the fact that it wasn't disclosed early enough."

Crash investigation

The downing of the plane happened hours after Iran fired missiles at U.S. forces in Iraq and was bracing for a U.S. counterstrike that never came. Iran's missile attacks, which caused no casualties, were in retaliation for what the United States called a self-defensive strike that killed top Iranian general Qassem Soleimani in Baghdad on Jan. 3.

A handout picture provided by the Iranian Presidency on Jan. 15, 2020, shows President Hassan Rouhani signing a book carrying the names of the victims of the Ukraine Flight 752 downing.

Meanwhile, Ukraine said Wednesday it asked Iran to give it the black box flight recorders from the Ukrainian plane that went down last week.

A statement from Ukraine's prosecutor's office said it is taking all necessary measures to ensure the recorders are properly decrypted and to preserve all evidence as investigators carry out their probe of the incident.

Alexander Ruvin, director of the Kyiv Scientific Research Institute of Forensic Science, told Ukrainian media after returning from leading an investigation team in Iran that Iranian specialists were due to arrive in Kyiv on Wednesday, and that analysts expect to begin examining the flight recorders on Monday.

Ukrainian President Volodymyr Zelenskiy has said he and Rouhani agreed that experts from their countries would work together, including on deciphering the black boxes. Zelenskiy and French President Emmanuel Macron also agreed to have French specialists help with that work.