The explosions are due to attacks by the US or Israel, according to a brief report from the Mehr news agency.
A bridge outside the city of Qom was also reportedly attacked by "enemy projectiles," according to statements in Iranian media.
The Israeli military announced around noon on Tuesday that it had carried out a large-scale wave of attacks on infrastructure throughout Iran. The military also urged Iranians to avoid train travel, as it "involves a danger to life."
The Iranian Revolutionary Guard, in turn, threatens to deprive the United States and its allies of access to oil for several years if the country's "red lines" are crossed, AFP reports. According to the statement, Iran has until now "shown great restraint" in terms of which targets could be subject to retaliation - "but all these reservations have now been lifted."
Kharg is a small island located a few miles off the coast of Iran in the northern Persian Gulf. Almost all of Iran's oil exports pass through the island, as it is the only place where the largest tankers can dock.
There are oil terminals and depots there. The US attacked Kharg in mid-March, but emphasized at the time that no attacks were directed at oil.
President Donald Trump has threatened to "wipe out" Kharg, among other places, if Iran does not meet American demands. However, attacks on the island are believed to have consequences for the global energy crisis and a more lasting intervention is considered difficult to implement given the island's proximity to the coast.
