Advisers to United States President-elect Joe Biden believe the Trump administration is trying to make it harder for Biden’s Democratic administration to re-engage with Iran.

The United States on Wednesday blacklisted two Iranian foundations controlled by Supreme Leader Ayatollah Ali Khamenei and their subsidiaries, saying the institutions enabled Iran’s elite to sustain a “corrupt” system of ownership over large parts of the economy.

The designations announced by the US Department of the Treasury target Execution of Imam Khomeini’s Order (EIKO) and Astan Quds Razavi (AQR), their leaders and subsidiaries. These are the latest actions to reinforce the “maximum pressure” campaign on Iran pursued by US President Donald Trump’s administration.

“These institutions enable Iran’s corrupt leaders to exploit a system of ownership over a wide range of sectors of Iran’s economy,” US Secretary of State Mike Pompeo said in a statement.

US-Iranian tensions have risen since Trump two years ago abandoned the 2015 Iran nuclear deal and restored harsh economic sanctions designed to force Tehran into a wider negotiation on curbing its nuclear programme, development of ballistic missiles and support for regional proxy forces.

The Trump administration has piled a barrage of sanctions on Iranian officials, politicians and companies but has so far failed to lure the Iranian government back to the negotiating table.

US officials have said there will be no slowdown in the pressure campaign on Iran in the final days of the Trump administration.

On Tuesday, Pompeo said without providing hard evidence that al-Qaeda had established a new home base in Iran and that it was time “for America and all free nations to crush the Iran-al-Qaeda axis”.

Republican Trump is due to hand over power on January 20 to Democratic President-elect Joe Biden, who has said the US will rejoin the nuclear deal “if Iran resumes strict compliance”.

Advisers to Biden believe the Trump administration is trying to make it harder for him to re-engage with Iran.

With stakes in nearly every sector of Iran’s economy, EIKO built its empire on the systematic seizure of thousands of properties belonging to religious minorities, business people, and Iranians living abroad, according to a 2013 Reuters news agency investigation, which estimated the network’s holdings at about $95bn.

AQR is a multibillion-dollar religious conglomerate that owns mines, textile factories, a pharmaceutical plant and even major oil and gas firms. The heads of both AQR and EIKO are appointed by Khamenei.

“EIKO has systematically violated the rights of dissidents by confiscating land and property from opponents of the regime, including political opponents, religious minorities, and exiled Iranians,” the Treasury said in a statement.

The sanctions freeze any US assets of those targeted and generally bar Americans from doing business with them. Anyone who engages in certain transactions with these individuals and entities runs the risk of being hit with US sanctions.