Italian embassy officials confirmed the four men were abducted from their hotel in Kerman, a city 800km (500 miles) southeast of the capital, Tehran.

An Iranian, believed to be their tour guide, was also taken hostage on Saturday.

The kidnapped men include two Spanish priests, named by the Spanish Foreign Ministry as Joaquin Fernandez and Cosme Puerto. The third Spaniard as Pedro Garcia.

Three men and two women armed with automatic weapons abducted the Spaniards as they ate dinner at their hotel. The Italian was taken from his room.

The BBC's Barbara Plett: "Taken from their hotel room"

Kerman's head of security, Abbas Doagooie, quoted by the Iranian state news agency, Irna, said the kidnappers were being pursued by security forces.

He said all routes out of the province were being monitored.

No group has admitted being responsible for the kidnapping but Iranian state radio has referred to them as armed bandits - a term which usually means drug traffickers.

And a BBC correspondent says the region is a known route for drugs being smuggled from Pakistan and Afghanistan.

Previous kidnappings

The Spanish embassy in Tehran has contacted the Iranian authorities to seek a prompt solution to the kidnapping.

The incident comes one day after Iranian President Mohammad Khatami ordered an investigation into the harassment of foreign tourists, particularly women, during last week's eclipse of the sun.

The kidnapping is at least the third mysterious attack on foreigners in Iran this year.

Irna reported in February that an armed robber kidnapped and killed a German banker in Kashan, which lies in central Iran about 710km (440 miles) north of Kerman.

In June, three Italians were abducted in southwestern Iran and freed unharmed after a week in captivity.

The reasons for the kidnapping were never disclosed, nor were any details offered on how it was resolved.

The latest kidnapping comes after foreign tourists converged on Iran last week as it was one of the best sites to watch Wednesday's solar eclipse.

There were newspaper reports that some tourists in the historic city of Isfahan, south of Tehran, had been harassed by Islamic vigilantes.

BBC correspondents say President Khatami has been trying to attract foreign tourists as part of a desperate attempt to bring hard currency into the country.