Iranian Foreign Ministry spokesman Abbas Mousavi said on Friday that the Swiss envoy was notified of Tehran's "strong protest".
"He was told that Washington's move is a blatant instance of state terrorism and the US regime is responsible for all its consequences," he said.
Earlier on Friday, the IRGC confirmed that Major General Soleimani, the commander of the Quds Force of the IRGC, had been assassinated in US airstrikes in Baghdad.