The US Treasury Department has slapped sanctions on an Iranian paramilitary group along with a network of businesses that were providing it financing, as part of Washington's campaign of maximum economic pressure against Tehran.

Iran yesterday called the sanctions against its paramilitary Basij group an act of "blind vindictiveness".

In announcing the sanctions, the Treasury said a network of more than 20 businesses known as the Bonyad Taavon Basij was financing the Basij Resistance Force, a component of Iran's Islamic Revolutionary Guard Corps (IRGC).

It also accused the hardline militia of sending child soldiers to Syria in support of President Bashar al-Assad's regime.

The Basij, a paramilitary force formed soon after the 1979 revolution, is one of the Iranian regime's primary enforcers of internal security with branches in every province and city of Iran, according to the US Treasury.