MEHRIZ, Yazd Province Iran's police on Sunday arrested 100 illegal Afghan immigrants crammed on a truck heading for Isfahan from this central city.

Mehriz police department said that the aliens will be repatriated after undergoing legal procedures.

Three days ago, 100 other Afghan aliens were arrested in the same district.

Since March 20, 2000, start of the current Iranian calendar year, 3,000 illegal Afghan immigrants have been arrested in Yazd Province.

The great number of Afghans living in Iran is commonly cited as one of the reasons contributing to the high rate of unemployment and drug abuse in the country.

Some 1.4 million Afghans still remain in Iran, half of them illegal residents, according to official government reports.

An Iranian government official said recently that about 500 Afghans manage to jump the border to Iran daily through Sistan-Baluchestan border of Iran.

Iran and the United Nations High Commissioner for Refugees (UNHCR) reached an agreement last April for the voluntary repatriation of Afghan refugees.

Iran is a major transit route for drugs from Afghanistan and Pakistan to the west and has also large domestic drug problem.

Last July, the Iranian authorities started constructing outposts and a barbed wire fence with electronic monitoring devices along the 945-kilometer (587-mile) border with Afghanistan. A budget of 200 billion rials ($25 million) was allocated for the project.

Meanwhile, Iran's police have killed five armed Afghan bandits and arrested 145 others in this northeastern province bordering Afghanistan over the past several days, sources said Sunday.

Provincial police said the killings and arrests took place after two separate shootouts in Gonabad and Taibad regions in this province.

Five assault rifles as well as cartridges and bullet magazines were also seized.

Armed bandits are involved in kidnapping, drug trade, and hostage-taking in provincial villagers.