Iran said on Saturday its security forces had arrested a network of agents working for Israel before they were able to carry out sabotage and "terrorist operations", state media reported.
The announcement by Iran's Intelligence Ministry came amid heightening tensions with Israel over Tehran's nuclear programme.
"This network's members were in contact with (Israel's) Mossad spy agency through a neighbouring country and entered Iran from (Iraq's) Kurdistan region with advanced equipment and strong explosives," the ministry said in a statement carried by state media.
The Israeli Prime Minister's Office, which oversees Mossad, declined to comment.
Iran often accuses its enemies or rivals abroad, such as Israel, the United States and Saudi Arabia, of trying to destabilise the country.
The Intelligence ministry did not say how many people were arrested and did not divulge their nationality. The network planned "acts of sabotage and unprecedented terrorist operations in sensitive locations", its statement said, without giving details.
Earlier this month, US President Joe Biden and Israeli Prime Minister Yair Lapid signed a joint pledge to deny Iran nuclear arms.
Tehran says its nuclear programme is peaceful and denies seeking nuclear weapons.