TEHRAN (Reuters) – Iran hanged 20 drug traffickers yesterday, official media reported, days after putting to  death 12 other convicted criminals.

The traffickers were executed in a prison in the city of  Karaj west of Tehran after being convicted for buying, selling  and possessing various drugs, IRNA news agency said.

A total of 700 kg of heroin, cocaine and opium had been  seized from the convicted traffickers, who were between 35 and  48 years old, IRNA said.

Murder, adultery, rape, armed robbery, apostasy and drug  trafficking are all punishable by death in the Islamic Republic. The human rights group Amnesty International has listed Iran  as the world’s second most prolific executioner in 2008 after  China, and says Iran executed at least 346 people last year.

Iranian media reported earlier this week that six drug  traffickers were executed in a prison in Qom on Wednesday and  six people were hanged for murder in Tehran’s Evin prison on  Tuesday.

European governments and Western rights groups have  criticised Iran for an increase in the number of executions  since authorities began a campaign against “immoral behavior”  in 2007.

Iran says it is implementing Islamic law and rejects  accusations it is violating human rights, accusing the West of  double standards and hypocrisy.

Iran shares a 900 km (560 mile) border with Afghanistan and  is used by well-armed gangs to smuggle drugs made from Afghan  opium poppies to the West, despite the efforts of Iranian  police. Up to 2 million of Iran’s 70 million people are  estimated to use narcotics.