Saudi Arabia on Wednesday said it would reveal evidence showing Iran was behind the attack on its oil facilities as Tehran threatened to retaliate “immediately” if any action is taken against it.

The Saudi Defense Ministry said it would present “material evidence and Iranian weapons proving the Iranian regime’s involvement in the terrorist attack.”

Iran reiterated that it played no part in the strikes on the Abqaiq refinery and the Khurais oil fields on Saturday that knocked out half of Saudi’s oil production ​as it aired the threat of retaliation.

“If any action takes place against Iran, the action will be faced by Iran’s answer immediately,” ​state-run news agency ​IRNA quoted ​a note sent to Swiss diplomats.

The development comes as Secretary of State Mike Pompeo is expected to meet with Saudi Crown Prince Mohammad bin Salman​ in Jeddah to coordinate efforts against “Iranian aggression,” the US Mission to the United Arab Emirates said. ​

The prince, in a phone call with South Korean President Moon Jae-in, said the attack posed “a real test of global will” to counter subversive acts that threaten international stability.

President Trump has said he doesn’t want to start a war but insisted the US is “prepared more than anybody.”

​Iranian-backed Houthi insurgents fighting in Yemen have claimed responsibility for the attacks on the installations.