TEHRAN, Iran (AP) — A leading European Union diplomat was holding talks in Tehran amid hopes that an agreement to restore Iran’s tattered nuclear deal with world powers could be completed. The meetings Sunday between Iranian officials and the EU’s envoy, Enrique Mora, come at a sensitive moment for talks to revive the 2015 deal that curbed Iran’s nuclear program in exchange for sanctions relief. The glimmers of a resolution to some of the thorniest issues in the negotiations have emerged. Nuclear talks broke off earlier this month as last-minute wrangles in Vienna coincided with Russia’s invasion of Ukraine and financial sanctions imposed by the West on Moscow. But officials have since made encouraging noises.