The latest round of European Union sanctions on Iran, which came into effect Tuesday, were met with fierce criticism in Tehran, reported dpa.
More than 30 entities were added to the sanctions list, and the assets of Iranian Energy Minister Majid Namjoo were frozen.
The EU journal said the restrictions apply to the National Iranian Oil Company and 25 subsidiaries, the National Iranian Gas Company, the National Iranian Oil Refining and Distribution Company, and the National Iranian Tanker Company.
Some of the companies have offices abroad, including in Britain and Switzerland, the EU said.
The state-owned Bank of Industry and Mine, and Cooperative Development Bank were targeted for providing "financial support to the government," the EU said. Trade Capital Bank has also been singled out for sanctions.
Iran's energy and petroleum ministries, which both provide "a substantial source of revenue for the Iranian government," will be subject to asset freezes.
Namjoo, who also serves as a member of the council which formulates Iran's nuclear policy, is banned from entering the EU.
Iran described the sanctions as "futile" and said they would build solidarity in the country.
"These pressures are illogical, inhuman and without any principles and therefore futile and just strengthening the nation's solidarity," Foreign Ministry spokesman Ramin Mehmanparast told reporters in Tehran.
"By acting stubborn and following a miscalculation, these countries are distancing themselves from a suitable settlement and will eventually achieve nothing."
Mehmanparast reiterated Iran's readiness to resume nuclear negotiations with the world powers.
Iran's supreme leader Ayatollah Ali Khamenei said that the new sanctions would not cause Iran to make concessions on its nuclear programme.
In a speech carried by ISNA new agency, Khamenei called the EU "too insignificant and too weak to bring us to our knees and force us to surrender to your demands at the negotiation table."
He said the aim of the sanctions was to force Iran to reopen nuclear talks with six world powers.
"It was not Iran which left the nuclear negotiations and therefore there is no need to force Iran for any return," said Khamenei.
Foreign ministers of the 27-member EU bloc agreed to the sanctions Monday during a meeting in Luxembourg.
Iran insists its nuclear programme is for peaceful purposes, but the West fears Tehran is seeking to develop atomic weapons. The EU has increasingly targeted the country's energy sector, with an oil embargo imposed earlier this year, in a bid to force it to engage in international negotiations over the programme.