The UK Treasury has frozen the assets of five Iranians suspected of involvement in a plot to assassinate the Saudi ambassador to the US.
Among those affected are two men who have been charged in the case - Manssor Arbabsiar, a 56-year-old US citizen of Iranian origin, and Gholam Shakuri, an alleged member of the Quds Force of the Iranian Revolutionary Guard.
Also named are Major General Qasem Soleimani, 54, a Quds commander who allegedly oversaw the plot, 51-year-old Hamed Abdollahi and Abdul Reza Shahlai.
The US froze the assets of the same five men a week ago.
It is understood that Soleimani, Abdollahi, Shahlai and Shakuri are senior officers from the Quds Force, an elite division of the Revolutionary Guard responsible for foreign operations.
Arbabsiar was arrested at New York's JFK Airport on September 29. He and Shakuri, who remains at large, were named last week in a criminal complaint in connection with the alleged murder plot.
US Attorney General Eric Holder announced last week that the American authorities had foiled an extraordinary plot to kill Saudi envoy Adel al-Jubeir.
An Iranian group planned to employ Mexican drug traffickers to kill Jubeir with a bomb as he ate at a restaurant, he said. Following his arrest, Arbabsiar is said to have confessed that he was working under the instruction of individuals in Iran who he understood to be senior officers of the Quds Force.
The Iranian authorities in Tehran have denied the plot, dismissing the US claims as "American propaganda".