About 1,200,000 jobs are held by foreigners in Iran, an official was quoted as saying by the Tehran Times Sunday.
The official added that most of foreign residents live in Iran illegally.
"Over two-thirds of nearly three million foreign residents do not have valid residence permits," he noted.
According to the paper, most of the illegal resident live in the eastern province of Ardebil.
The official said that the authorities will soon carry out a plan to identify and register all foreign residents in the province, adding that the plan will be implemented in four phases.
On Sunday, Iranian police arrested 111 Afghan nationals who had illegally entered the northeastern Khorassan province on the border with Afghanistan.
It said the illegal Afghan immigrants, who were spread across nine cities in Khorassan province, were arrested during the past three days.
There are around 1.4 million Afghans in Iran, and authorities believe half of them are in the country illegally – Albawaba.com