Iran has hanged 22 people following convictions for drug trafficking.

An Iranian state-owned newspaper reported the executions on Monday, saying they happened on Sunday. The reports says the hangings were performed in Tehran's Evin prison and in a jail in Karaj, 25 miles west of the capital.

Iran carries out executions for crimes including murder and illicit drug running. Iran is a major transit corridor for the smuggling of opium from Afghanistan.

Iran is coming under increased scrutiny for the number of executions it carries out. Human rights groups say Iran executes more people per capita than any other country in the world.

The United Nations human rights chief, Navi Pillay, said in March there has been a dramatic increase this year in the number of executions carried out in Iran. She said the rate was three times higher than that of last year.