Kenyan officials have revealed that two alleged Iranian agents have been arrested over an apparent plot to attack Israeli and other targets.
The men, who were arrested last month, were holding 15 kilograms of explosives that could be used to build a powerful bomb.
Officials told the Associated Press that such a device could be used to bring down a large building, such as a hotel.
Ahmad Abolfathi Mohammad and Sayed Mansour Mousavi appeared in court in Kenya last week.
In the last few month authorities in countries including Thailand and Azerbaijan have foiled planned attacks, allegedly by Iranian agents. Israel also blamed Iran for an attack in Delhi in February.
"There are no limits to the Iranian terror," said Benjamin Netanyahu, the Israeli Prime Minister. "After Iran sent its people to assassinate the Saudi ambassador on American soil and carry out attacks in Azerbaijan, Bangkok, Tbilisi and New Delhi, now its intention to carry out attacks in Africa is revealed.
"The international community needs to fight the world's greatest exporter of terror."
It is a decade since an Israeli-owned hotel in Mombasa was bombed by al-Qaeda linked Islamist militants, leading to the death of 13 people.