Iran has sentenced eight people to death over attacks claimed by the Islamic State group last year.

Mousa Ghazanfarabadi, the head of the Tehran Revolutionary Courts, told state TV Sunday that they were found guilty of aiding the five militants who attacked parliament and a shrine to Iran's revolutionary leader, Ayatollah Ruhollah Khomeini.

The attacks last June killed 18 people and wounded more than 50. Security forces killed all the attackers.

Ghazanfarabadi says 18 other people face trial over the attacks. Those convicted have 20 days to appeal. The trials began last month.