Iran’s Supreme Leader Ayatollah Ali Khamenei said on Thursday his country had delivered a "slap to America’s face” with its strike on a U.S. airbase in Qatar, and warned against any further attacks in his first public comments since a ceasefire was declared with Israel after 12 days of war.

The aging leader’s message was defiant but somber, delivered in front of a tan curtain flanked by an Iranian flag and a portrait of his predecessor.

In public, Qatar was insisting on the right to defend itself after Iran attacked a U.S. military site in the emirate. Behind the scenes, it was already mediating a truce between Israel and Iran.