Tehran accuses Washington of ‘naked economic aggression’ and urges UN’s top court in The Hague to nullify US sanctions.

The United States vowed to fight Iran before the International Court of Justice (ICJ), calling Tehran’s move to question the legality of recently reimposed sanctions an attempt to interfere with its national security.

US Secretary of State Mike Pompeo issued the statement on Monday as legal proceedings began before the court in The Hague.

“Iran’s filing with the ICJ is an attempt to interfere with the sovereign rights of the United States to take lawful actions, including reimposition of sanctions, which are necessary to protect our national security. The proceedings instituted by Iran are a misuse of the court,” said Pompeo.

Iran has asked the international court to order the US to lift sanctions against Tehran after Washington unilaterally pulled out of the 2015 nuclear deal.

In the Netherlands on Monday, Mohsen Mohebi, the lawyer representing Iran, condemned the US for “naked economic aggression” in the first session of the case.

The measures have had “immediate damaging consequences on Iran and the Iranian people”, Mohebi said.

Iran said the US sanctions violate terms of a little-known 1955 friendship treaty between the two countries.

Tehran filed its case before the ICJ in late July, calling on the top UN tribunal’s judges to order the immediate lifting of sanctions, which it said would cause “irreparable prejudice”.

‘Won’t shy away’

Pompeo said lawyers would “vigorously defend” the United States.

“We will continue to work with our allies to counter the Iranian regime’s destabilising activities in the region, block their financing of terror, and address Iran’s proliferation of ballistic missiles and other advanced weapons systems that threaten international peace and stability. We will also ensure Iran has no path to a nuclear weapon – not now, not ever.”

The United States rejection of the nuclear deal is not backed by some key allies. Last week, the European Union announced its first financial support package to help bolster Iran’s flagging economy, part of the bloc’s commitment to keep the Iran nuclear deal alive.

The US will formally respond in oral arguments on Tuesday.

American lawyers are expected to argue the UN court does not have jurisdiction in the dispute, the friendship treaty is no longer valid, and the sanctions Washington levied against Tehran do not violate the deal.

The ICJ has so far ruled the 1955 treaty is still valid, even though it was signed long before the 1979 Islamic Revolution that triggered decades of hostile relations with Washington.

The hearings – essentially a request by Iran for a provisional ruling – will last four days with a decision to follow within a month.

The ICJ is the United Nations tribunal for resolving international disputes. Its rulings are binding but it has no power to enforce them, and verdicts have been previously ignored by some countries, including the US.

In an interview with Al Jazeera, Maya Lester, an international sanctions lawyer, said the 1955 treaty between Iran and the US remains in force and had been previously invoked by both countries before the international court.

“Certainly, if the court thinks that there’s been a violation, it won’t shy away from saying so,” Lester said, adding that other courts in Europe have also looked into the legality of the sanctions.

“But this case is unusual as it is a wholesale attack on international law grounds, on the current snapback of US sanctions against Iran,” she said.

“In principle, the ICJ could declare these sanctions unlawful and in breach of international law.”

‘Psychological war’

US President Donald Trump pulled out of the landmark 2015 nuclear pact between Iran and world powers and announced unilateral plans to restore sanctions against Tehran.

Under the deal, Iran reined in its nuclear programme, under UN monitoring, and won the removal of devastating international sanctions in return.

Iran’s Foreign Minister Mohammad Javad Zarif accused the US this week of waging “psychological war” against Tehran and its business partners.

Although European allies have protested Trump’s move, most Western companies intend to adhere to the sanctions, preferring to lose business with Iran rather than being financially punished by the US or barred from doing business there.