The US Treasury Department has slapped financial sanctions on two more Iranian groups it claims are involved in the country’s ballistic missile programme, the latest legal move announced by Washington on Thursday, against the government in Tehran.

Despite the historic agreement struck in July between the countries to restrict Iran’s nuclear programme, the development of missiles that could theoretically one day still carry nuclear warheads is one of a number of issues that continue to stoke tensions.

Recently, the US imposed similar sanctions on 11 other companies and individuals alleged to be involved in the programme after the test-firing of rockets last month that it claims are violation of a United Nations resolution.

The latest groups to join that list – subsidiaries of Shahid Hemmat Industrial and the Islamic Revolutionary Guard Corps Al-Ghadir Missile Command – are said to have been involved in test launches on 8 and 9 March.

Simultaneously, the US administration also targeted two British companies – Aviation Capital Solutions and Aircraft, Avionics, Parts & Support – that it claims are providing support to an Iranian airline flying weapons and soldiers to the war in Syria.

Alongside a similar aviation support company in the United Arab Emirates, the firms and several executives will be subject to financial sanctions making it hard to operate in US markets.

“Iran’s ballistic missile program and its support for terrorism pose a continuing threat to the region, to the United States, and to our partners worldwide,” said US Treasury official Adam Szubin in a statement. “We will continue to use all of our tools to counteract Iran’s ballistic missile program and support for terrorism, including through sanctions.”

The new measures, marking a shift toward more combative relations with Iran, came on the same day as the Department of Justice unsealed charges against seven Iranian hackers accused of disrupting computer systems at American banks and a small dam north of New York on behalf of the Iranian government.

The following changes have been made to OFAC's SDN List: