Iran tracks down and kills Islamic State suspects, including alleged mastermind of Tehran attacks

Several suspected militants, including the alleged mastermind of twin attacks in Tehran last week, were tracked down, detained or killed by Iranian authorities, a security official and a minister confirmed.

Police killed four Islamic State [IS] suspects in the southern province of Hormozgan, the ISNA news agency reported on Monday, quoting police chief Azizollah Maleki.

"Two of the killed criminals were foreign nationals... while the identity of other members is being investigated," Maleki said, adding that weapons and an IS flag were seized during the raid.

Dozens of suspects have so far been arrested in the ongoing investigations into the attacks that killed 17 people on Wednesday - the first assault in Iran to be claimed by the Islamic State militant group.

Authorities said five Iranians, who had joined IS and travelled to its Iraq and Syria bastions, carried out Wednesday's attacks on the parliament and the shrine of revolutionary leader Ayatollah Ruhollah Khomeini.

Late on Saturday, Intelligence Minister Mahmoud Alavi said the alleged mastermind behind the attacks had been tracked down and killed outside the country.

"The mastermind who controlled the team... who had fled outside the country... paid the price for his crimes, with the cooperation of intelligence services of allied countries," Alavi told state television, without providing further details.

At least 41 IS suspects have been arrested since the attacks, according to Alavi, who said Iran has dismantled suspected militant cells with increasing frequency in recent months.

From January to  March 2017 "we dismantled 45 cells, while in the past two-and-a-half months alone we have dismantled more than 25 terrorist cells," he said.

Officials have reported the arrests of suspected IS members in and around Tehran, as well as in the country's centre, southern governorates, and western provinces near the Iraqi border.