Saudi Arabian authorities last week broke into a terrorist cell that was trained by Iran's Revolutionary Guard, arresting 10 people and seizing weapons and explosives, a state security spokesman said on Monday.
A statement issued by the Presidency of State Security, which is overseen by the King and Crown Prince, said three of those detained had received training in Iran by the paramilitary group in October 2017 on manufacturing explosives.
The weapons and explosives were confiscated at a house and a farm, the statement said.
The cell was broken up by security forces on September 23, with weapons such as sniper rifles and pistols confiscated at two locations, the security agency said.
The security body did not provide much further detail or evidence regarding the alleged cell, such the location where the militants were arrested.
The identities of those detained have not been revealed because an investigation is still ongoing, the statement said.
Iran's foreign ministry dismissed the Saudi claims as "completely fabricated".
"Saudi rulers have cast aside political rationality and now... have chosen to fabricate lies against Iran as a means to distract public opinion and a method to cover their failed attempts," spokesman Saeed Khatibzadeh said in a statement.
Saudi Arabia and Iran are longtime rivals, though tensions have steadily increased in recent years between the two countries, particularly since the Trump administration began reimposing sanctions on Iran that effectively block it from selling its oil internationally.
Saudi Arabia has blamed Iran for being behind attacks on Saudi oil targets last year, including a missile and drone strike on Aramco’s largest crude oil processing plant in the eastern part of the kingdom.
Yemeni rebel Houthis claimed responsibility for that attack and Iran has denied involvement. A UN probe concluded the missiles were of Iranian origin.
The Saudis also accuse Iran of interfering in Yemen by backing the Houthis when they ousted the internationally-backed government from the capital in late 2014.
Saudi Foreign Minister Faisal bin Farhan Al Saud on Sunday spoke with his US counterpart Mike Pompeo on Sunday.
The two discussed important work to advance humanitarian assistance and peace in Yemen, the need to increase Gulf stability, and the Abraham Accords signing, the US State Department said.
This month, Bahrain said it broke up a plot by militants backed by Iran earlier this year to launch attacks on diplomats and foreigners in the island nation home to the US Navy’s 5th Fleet.