Iran has suspended the fifth round of talks with regional rival Saudi Arabia, a website affiliated to Iran's top security council reported on Sunday.

Nour News, which is close to the secretary of Iran's Supreme National Security Council (SNSC), Ali Shamkhani, on Sunday broke the news of the “temporary suspension” of the fifth round of negotiations.

"Iran has unilaterally suspended talks with Saudi Arabia," the report said, without providing a reason. The announcement was unexpected as Iran had been publicly more enthusiastic about the talks than Saudi Arabia.

The report said no specific date had been scheduled for a new round of talks. Iraqi Foreign Minister Fuad Hussein announced on the sidelines of the Antalya Conference on Saturday that the fifth round of talks would be held in Baghdad on Wednesday

The news comes a day after Saudi Arabia carried out mass executions of 81 men that activists said included 41 Shiite Muslims.

Sunni Muslim Saudi Arabia and Shiite Iran, which are locked in proxy conflicts around the region, launched direct talks hosted by Iraq last year at a time when global powers were trying to salvage the 2015 nuclear pact with Tehran, and as UN-led efforts to end a war in Yemen stalled.

Riyadh cut ties with Iran in 2016 when mobs attacked its embassy in Tehran after Riyadh executed 47 dissidents including the leading Shi'ite cleric Sheikh Nimr al-Nimr. An Iranian lawmaker had said in January that Tehran and Riyadh were getting ready to reopen their embassies.