The Iranian interior ministry says it's given hundreds of thousands of Afghan refugees, who are in the country illegally, three weeks to leave.

It's the latest in a series of similar pronouncements over recent years, and comes at the same time as what correspondents say is an increase in the number of Afghans being expelled from Iran.

The BBC Iranian affairs analyst says the government is under pressure to reduce unemployment in the country and some officials have blamed the Afghan refugees for making the problem worse.

There are estimated to be almost one-and-a-half million Afghan refugees in Iran.