Tehran accused Riyadh on Friday of "sowing division" in the region to Israel's advantage, after the kingdom hosted summits of Gulf and Arab leaders to rally support against the Islamic republic.
Saudi Arabia has "continued to sow division between Islamic countries and in the region, which is the wish of the Zionist regime", Iran's foreign ministry spokesman Seyed Abbas Mousavi said.
"We see the attempts by Saudi Arabia to rally neighbouring and Arab countries against Iran as the continuation of futile attempts by America and the Zionist regime," he added.
Mousavi expressed disappointment that Riyadh intended to level the same "baseless allegations" against Tehran at a summit of the Organisation of Islamic Cooperation in Makkah early on Saturday, "exploiting" its role as host.
Saudi Arabia's King Salman on Friday ratcheted up the rhetoric against arch-rival Iran, calling on Arab states to confront its "criminal" actions after attacks on oil installations sparked fears of a regional conflagration.
The king's remarks came at the start of two back-to-back emergency summits in Makkah in the early hours, which drew near-unanimous support for the Sunni kingdom from Gulf and Arab states — with the notable exception of Iraq.
The summits came after hawkish US National Security Advisor John Bolton said on Wednesday that Iran was "almost certainly" behind May 12 attacks on four ships, two of them Saudi oil tankers, off the United Arab Emirates.
Tehran dismissed the accusation as "laughable" and accused Bolton of pursuing "evil desires for chaos in the region".