The seizures ratcheted up tensions between Iran and the West already simmering over Iran’s tattered 2015 nuclear deal with world powers.
In a televised speech, Ayatollah Ali Khamenei urged the importance of nuclear energy for Iran, while again asserting that it had no interest in nuclear weapons.
Tens of thousands gathered in cities across Iran on Wednesday in a massive show of support for the regime after days of deadly unrest, state television showed.
In a dramatic shift from 2009, protesters now are chanting slogans against Khamenei and rejecting the ruling system.
A total of 21 people have died in five days of unrest across the country which began as protests over the economy before quickly turning against the Islamic regime as a whole.
Demonstrations are spreading across Iran and turning increasingly violent, but analysts say a lack of leadership and political support mean they may struggle to maintain momentum.
The supreme leader of Iran said in a statement on state television, that the 'enemies' of the country of joined hands to create problems for the regime.
Iran's Supreme Leader Ayatollah Ali Khamenei on Tuesday said that violence in Myanmar against the Rohingya Muslims marks the "death of Nobel Peace Prize".