The Ukraine International Airlines plane was brought down by a missile shortly after takeoff on Wednesday, killing all 176 passengers and crew on board.
Iran said earlier it unintentionally downed a Ukrainian jetliner outside Tehran, killing all 176 people aboard, in an abrupt about-turn after initially denying claims it was struck by a missile.
That attack was retaliation for the killing of Iran's top general, Qassem Soleimani, in an American airstrike in Baghdad.
Iran on Saturday admitted that it accidentally downed the Ukraine International Airlines (UIA) plane.
"We will not give the black boxes to the manufacturer (Boeing) and the Americans," Iran Civil Aviation Organisation head Ali Abedzadeh said, quoted by Mehr news agency.
According to the Iranian and Ukrainian officials, the crash, which happened shortly after take-off from Imam Khomeini airport in Tehran, left no survivors.
The stampede took place in Kerman, the hometown of Revolutionary Guard General Qassem Soleimani, as the procession got underway.
Qatar's foreign minister called for "dialogue" on Wednesday to resolve the Gulf diplomatic crisis, accusing Arab states that have cut ties with Qatar of trying to undermine the nation's sovereignty.
The four Arab nations, which also include the United Arab Emirates, Bahrain and Egypt, accuse Qatar of supporting extremism, a charge which it denies.
UN Security Council has told Qatar to sort out its differences with its Gulf neighbours, China's ambassador said, indicating the top UN body would not get involved in the dispute.
The response was delivered by Qatari Foreign Minister Al-Thani who made a short visit to Kuwait, which is acting as a mediator to resolve the diplomatic rift, the official said.
Egypt will host the foreign ministers of Saudi Arabia, the United Arab Emirates and Bahrain on Wednesday to discuss the crisis with Qatar, Cairo's foreign ministry said.
A deadline was extended Monday for Qatar to accept 13 demands by several Arab states in return for lifting a de facto blockade.
He was to meet later with Kuwait Foreign Minister Sheikh Sabah Khaled Al-Sabah, who has sought to work resolve the standoff.
Al-Jazeera Arabic account described the move as part of an "organised campaign" targeting it. Al-Jazeera has said it has come under cyberattack as well amid the diplomatic crisis.