Khalil Dardmand was arrested by police in the holy city of Mecca after completing his hajj rituals, Iran's foreign ministry said in a statement, without providing other details about the case.

Iran's top diplomat Hossein Amir-Abdollahian said he was hopeful that the pilgrim could return home soon with the help of Saudi Arabia.

"This ministry is using all its power to free this Iranian citizen as soon as possible," the statement quoted him as saying.

Nearly 780,000 pilgrims from abroad attended this year's hajj pilgrimage, according to Saudi officials.

Regional powerhouses Tehran and Riyadh have had no relations since 2016 when Iranian protesters attacked Saudi diplomatic missions in Iran after the kingdom executed opposition Shiite cleric Nimr al-Nimr.

Since April last year, Iraq has hosted five rounds of talks between Shiite-majority Iran and its Sunni rival, which support opposing sides in various conflicts across the region, including in Yemen.

Amir-Abdollahian said last month that Iran and Saudi Arabia were ready to move talks to a higher level, in the political and public spheres, after earlier rounds mainly at the level of security officials.

His Iraqi counterpart Fuad Hussein said on July 23 that his country was preparing to host a "public" meeting of his Saudi and Iranian counterparts.