US asked for 'proportionate response' to Qasem Soleimani's killing, says Iran
Soleimani, the commander of the Guards' Quds Force foreign operations arm, was killed early on Friday in a US drone strike in Baghdad, along with nine others, in an attack Iran's Supreme Leader Ali Khamenei has vowed to avenge.
Just hours later, Washington "resorted to diplomatic measures... on Friday morning", the Guards' Rear-Admiral Ali Fadavi said on Iranian state television.
They "even said that if you want to get revenge, get revenge in proportion to what we did", he said, as quoted on the broadcaster's website.
Fadavi did not specify how Iran had received the message, despite the fact Tehran and Washington have had no diplomatic relations for four decades.
In a separate television interview on Friday night, Iranian Foreign Minister Mohammad Javad Zarif said that "Switzerland's envoy transmitted a foolish message from the Americans this morning".
The Swiss official "was summoned in the evening and received a decisive response in writing... to the Americans' audacious letter", Zarif added.
|"The Americans must await severe revenge. This revenge will not be limited to Iran
- Ali Fadavi, Revolutionary Guards' Rear-Admiral
The Swiss foreign ministry confirmed on Saturday that its charge d'affaires had handed over a letter from Washington to the Iranians when he was summoned to the foreign ministry on Friday morning.
Switzerland's embassy in Tehran has represented US interests in the Islamic republic since ties were cut in 1980.
But Fadavi said the United States was not in a position "to determine" Iran's response.
"The Americans must await severe revenge. This revenge will not be limited to Iran," he said.
"The 'Resistance Front', with a vast geography, is ready to materialise this revenge," he added, referring to Iran's allies across the Middle East.
The Iran-backed Lebanese militant group Hezbollah has urged "resistance fighters worldwide" to avenge Soleimani's death.
Yemen's Iran-linked Houthi rebels and the leaders of several Tehran-backed Iraqi militia groups have also vowed a response.
"In case of war or any confrontation, Americans will suffer severe damage and if they show any madness, Iran's response would be tougher," a senior spokesperson for the Iranian army said on Saturday.
"[The] Americans have taken an irreversible step," Brigadier General Abolfazl Shekarchi told Mehr News Agency.