Tehran has condemned the US for imposing new sanctions on Iranian targets, among others, over alleged oil shipments to Syria, saying Washington will realize such bans are “futile” and “illogical.”

Foreign Ministry Spokesman Bahram Qassemi said on Wednesday that the latest sanctions were based on delusional excuses.

“These futile, illogical and ineffective sanctions on people and entities will definitely not produce the results desired by their designers and enforcers,” he said.

“Sooner or later they (the Americans) will become aware of the futility of what they thought,” he added.

On Tuesday, the US Treasury Department imposed sanctions on a total of six people and three entities for sending millions of barrels of oil to Syria.

The blacklist included two executives at the Central Bank of Iran, a Russian, a Syrian, an Iraqi and a Lebanese national as well as an Iranian entity and two Russian ones.

Under the administration of US President Donald Trump, Washington has taken an increasingly hostile approach toward Tehran in what is viewed by Iranian officials as an economic war.

Back in May, Trump withdrew his country from the 2015 Iran nuclear deal, called the Joint Comprehensive Plan of Action (JCPOA), in defiance of international objections.

Since then, the US has unleashed its "toughest ever" sanctions against Iran. It has also warned of severe penalties for the companies that evade the bans and engage in business with Iran.

Iran has stressed that the American pressure campaign and oppressive sanctions will definitely fail.

Washington is also critical of the Iranian and Russian role in Syria, where the two countries have been helping the Syrian government fight the militant groups, many of which have the US firm support.