The European Union this month announced a ban on Iranian oil imports in coordination with a U.S. decision to impose sanctions in Iran's financial and energy sectors.
Brig. Gen Massoud Jazayeri, deputy chairman of the Iranian Joint Chiefs of Staff, said the European efforts were counterproductive.
"These sanctions are aimed at exerting psychological pressures and hardship on the Iranian government and nation, but will lead nowhere," he was quoted by Iran's state-funded broadcaster Press TV as saying.
Jazayeri said the sanctions were a tactic of the "soft war" that Western allies were waging against Iran.
Iran's Ayatollah Ahmad Khatami said during a sermon Friday the EU ban was "not a new matter." He added that it was likely a move to affect March parliamentary elections.
Human Rights Watch said in a report this week that Iranian authorities were cracking down on reformist newspapers to silence dissent ahead of the March vote.
Western allies allege Iran is working on the technology needed to produce a nuclear weapon. Tehran insists its intentions are peaceful.