Iran has arrested 14 suspected members of the Islamic State jihadist group who were allegedly planning attacks in the country, authorities said on Friday.

The 14 members of "Islamic State-Khorasan have been arrested" in a series of operations, the intelligence ministry said in a statement cited by state news agency IRNA.

Islamic State-Khorasan, or IS-K, is the jihadist group's Afghanistan branch. "Khorasan" refers to a historical region that included parts of Iran, Afghanistan and Central Asia.

IRNA did not specify the nationalities of those arrested, nor when they were detained, but said they were being questioned in the provinces of Tehran, nearby Alborz, Fars in the south, and southwest in Khuzestan.

"The accused came into the country in the past few days aiming to carry out terrorist operations," the ministry statement said.

In January IS, a Sunni Muslim group, claimed twin blasts that killed more than 90 people at a memorial ceremony in Kerman, southern Iran.

It was the deadliest attack in Shiite Muslim-majority Iran since 1978.

At that time, then-interior minister Ahmad Vahidi said IS "was carrying out operations in the country in the service of the Zionist regime," a reference to Iran's arch-foe Israel.

Since war began in October between Israel and Hamas Palestinian militants in the Gaza Strip, tensions have soared between Israel and Iran.

In April, Iranian state media reported the arrest of three suspected IS members near Tehran.