India, Feb. 11 -- A top Iranian security official travelled on Tuesday to Oman, the Mideast sultanate now mediating talks between Tehran and Washington over the Islamic Republic's nuclear program aimed at halting a possible American strike. Ali Larijani, a former Iranian parliament speaker who now serves as the secretary to the country's Supreme National Security Council, likely carried Iran's response to the initial round of indirect talks held last week in Muscat with the Americans.

Larijani's entourage shared photos of him meeting with Omani Foreign Minister Badr al-Busaidi, the chief intermediary in the US-Iran talks, with what appeared to be a letter sheathed in plastic and sitting alongside the Omani diplomat. Iran has, in the past...