DUBAI (Reuters) - An Iranian court on Sunday sentenced eight men to death over attacks that killed 18 people at the parliament and Ayatollah Ruhollah Khomeini’s mausoleum last year, in the first deadly operation by Islamic State in the country.

The sentence, issued by a Revolutionary Court after a seven-session hearing, can be appealed in Iran’s Supreme Court, Musa Ghazanfarabadi, head of Tehran’s Revolutionary Court, told state television.

Ghazanfarabadi said courts will hear claims later filed by families of the victims against the United States and Saudi Arabia, which mainly Shi’ite Muslim Iran accuses of supporting Sunni Muslim militant group Islamic State. Both countries deny that accusation.

Islamic State claimed responsibility for the unprecedented attacks in Iran, in which suicide bombers and gunmen attacked the parliament and Khomeini’s mausoleum in Tehran.

Eighteen other suspects still face charges over the attacks, according to state media.

Iran has said that the five gunmen and suicide bombers who were killed had fought in Syria and Iraq, where Islamic State once held swathes of territory but is now in decline.