Tehran said it issued a temporary stay to Sherko Moarefi, a political activist who was to have been hanged last weekend. His lawyer, Khalil Bahramian, told The Guardian newspaper in London, however, that he "might be executed at any time."
Moarefi was arrested in 2008 on suspicion of being a member of Komala, a Kurdish opposition political party that Iran considers a terrorist organization.
London last week expressed outrage over the April 20 public execution of four men convicted of rape and murder charges. The British government said two of the men were juveniles.
"The United Kingdom condemns the use of the death penalty in all circumstances," Minister for the Middle East Alistair Burt said in a statement. "Death by strangulation and the execution of juvenile offenders are particularly abhorrent."
London said Iran has executed nearly 200 people so far this year. That's more than any other country except China executed in all of 2010.