The US wants to stop Iran's arms build-up by hook or by crook

Washington may even exploit a legal loophole to try and extend a UN embargo against Tehran

Iran's Islamic Revolutionary Guard Corps recently launched ballistic missiles as part of an exercise involving a mock-up aircraft carrier in the Strait of Hormuz. AP Photo

The prospect of Iran being able to buy weapons on the open market has prompted the Trump administration to launch a diplomatic offensive aimed at pressuring the United Nations to extend its arms embargo against Tehran when it comes up for renewal later this year.

The embargo was implemented under UN Security Council resolution 2231, passed in 2015 in support of the controversial nuclear deal negotiated under the aegis of former US president Barack Obama.

The embargo is due to expire on October 18, but attempts by Washington to persuade the UN to agree to an extension have foundered in the face of strong opposition from China and Russia, which have the power to veto any extension.

Both Beijing and Moscow have lent their support to Tehran during the latter's recent upsurge in tensions with Washington following US President Donald Trump's unilateral decision to withdraw from the nuclear deal in 2018. The Russians and Chinese argue that the American withdrawal from the agreement means that Iran should no longer be subjected to an arms embargo when the terms of the resolution expire in the autumn.

Iranian President Hassan Rouhani has already indicated that his regime intends to take full advantage of any relaxation in the terms of the arms embargo to rebuild his country’s depleted weapons arsenal. State-run Iranian television reported at the end of last year that Mr Rouhani had commented: “When the embargo is lifted next year, we can easily buy and sell weapons. This is one of those important impacts of this [nuclear] agreement.”

Washington has expressed particular concern that ending the arms embargo will enable Iran to buy sophisticated weaponry from Russia and China. Tehran is currently in the process of negotiating a wide-ranging trade deal with Beijing said to be worth around $400 billion over a 25-year period. Under the terms of the agreement, Tehran and Beijing are said to be working on a project to develop a military base in the Indian Ocean that will enable them to challenge America's long-standing military dominance in the region.

The agreement, which a senior aide to Mr Rouhani says should be signed by next March, encompasses closer military co-operation between the two countries, including weapons development, combined training and intelligence sharing. Washington has expressed concern that this will allow China and Iran to monitor more closely the activities of the US Fifth Fleet in the Gulf, as well as the joint US-UK military base on the Indian Ocean island of Diego Garcia.

Despite the arms embargo, Iran has continued work on developing its military strength, in particular by upgrading the numerous ballistic missile systems that have been linked with its nuclear programme.

The growing sophistication of Iran's missile capabilities was demonstrated earlier this week when the Islamic Revolutionary Guard Corps launched underground ballistic missiles at a mock-up American aircraft carrier that had been deployed in the Strait of Hormuz. The missiles, appeared to have been launched from Iran's desert plateau, suggest that the regime has developed a network of subterranean bases that can be used to threaten the US and its allies in the Gulf. Commenting on the exercise, Gen Amir Hajizadeh, the commander of the IRGC's aerospace division, told state TV: "We have carried out the launch of the ballistic missiles from the depths of the earth for the first time."

Moreover, the prospect of Iran having the freedom to rebuild its weapons arsenal comes at a time when there has been an upsurge in provocative activity by Tehran in the Middle East. Iran has been accused of increasing tensions with Israel after a team of Hezbollah fighters in Lebanon were reported to have attempted an attack on Israeli positions in their country's north earlier this month.

In an attempt to curb Iran’s military ambitions, which believes constitute a direct threat to the security of the Gulf region, Washington has launched a diplomatic offensive aimed at putting pressure on the UN to extend the arms embargo.

In a recent address to the Security Council, US Secretary of State Mike Pompeo delivered a blunt warning, arguing that the council was faced with a stark choice. It could “stand for international peace and security, as the United Nations’ founders intended, or let the arms embargo on the Islamic Republic of Iran expire, betraying the UN’s mission and its finest deals, which we have all pledged to uphold".

Mr Pompeo explicitly warned that a failure to renew the embargo would enable Iran to buy sophisticated weaponry from Russia, such as warplanes “that can strike up to a 3,000-kilometre radius”.

Tehran would also be able to upgrade and expand its fleet of submarines, thereby enabling it to threaten international shipping and freedom of navigation in the Gulf, Strait of Hormuz and the Arabian Sea. Allowing Iran access to new arms supplies would also enable it to continue supplying weapons to proxies, such as Hezbollah and Hamas, as well as maintain its support for the Assad regime in Syria.

Given that China and Russia are unlikely to alter their position on ending the arms embargo when the issue comes before the Security Council in October, the Trump administration is looking at a range of options to maintain the embargo. One option under consideration in Washington is for the US to point out that – despite the Trump administration’s withdrawal from the deal – it remains a participant in the nuclear agreement, and can therefore exercise a Security Council provision to veto the embargo’s expiration.

Whether or not this dubious tactic succeeds, what is beyond doubt is that any attempt by Iran to rebuild its weapons arsenal will, at the very least, encounter stiff resistance from Washington.

Con Coughlin is the Telegraph’s defence and foreign affairs editor