Tehran - Iran called new US sanctions against its paramilitary Basij group an act of "blind vindictiveness" on yesterday.
"America's new sanctions are a clear insult to international and legal mechanisms and a result of the American government's blind vindictiveness against the Iranian nation," said foreign ministry spokesman Bahram Ghasemi.
He called Washington's "lack of adherence to international legal mechanisms" a threat not only "to the Iranian people's interests but also the world's stability and security."
On Tuesday, the US Treasury Department slapped sanctions on a network of more than 20 businesses it said had financial links to the Basij paramilitary group, which enforces internal security in Iran.
The US pulled out of a landmark 2015 nuclear accord between Iran and six world powers in May and is reimposing punishing sanctions on the Middle Eastern country, hoping to pressure Tehran into what President Donald Trump calls a "better deal".
Iran's Bank Parsian, among the companies sanctioned on Tuesday, said in a statement that the measures would change little.
"This bank's international activities using dollars and America had ceased for years," it said.
Iran's biggest steel company, also on the sanctions list, similarly dismissing the measures as "nothing new".
In a statement to investors, Mobarakeh Steel Company said: "International sanctions are nothing new and Mobarakeh has faced them throughout the years just like other sectors of the Iranian economy.
"This will not disrupt the company's production, financial activities and exports," it added.
- 'Can't stop exports' -
Mobarakeh, the largest steelmaker in the Middle East and North Africa region according to the US Treasury, was accused of supporting the Mehr Eqtesad Iranian Investment Company, which is linked to Iran's Revolutionary Guards, according to the US Treasury.
A steel industry expert in Tehran said the sanctions would hurt Mobarakeh, but without entirely stopping its exports.
"The company will now have problems doing anything, be it attracting financing from abroad or having any overseas accounts," Mojtaba Fereydouni told AFP.
"But sanctions cannot just stop Iran's exports. You just ship it to a third country, unload the shipments there and leave it for a few days. Then you reship them from there with no mention of Iran and a new certificate of origin.
"All this will incur a cost of $20-$30 on each tonne, but it's not impossible," he added.
Iran's steel industry was targeted under the first wave of US sanctions reimposed in August.
But Mobarakeh said it had indigenised its production line.
Fereydouni added that it had set up a factory to produce the key raw material of electrode graphite, which is normally imported, primarily from India.
Iran is the 10th biggest crude steel producer, according to the World Steel Association.
The government said it exported $2.53 billion of steel products between March and September, up 53 percent on the previous year -- an increase which is thought to be driven by a rush by buyers to make purchases before sanctions hit.