The United States has threatened to impose a 25 percent tariff on imports of European cars if European Union governments continue to back the nuclear deal, according to German Defence Minister Annegret Kramp-Karrenbauer.
The 2015 agreement was struck in Vienna between Iran and France, Britain, Germany, the United States, China and Russia.
But it has threatened to collapse since President Donald Trump unilaterally withdrew the United States in 2018, before reimposing a series of intensifying economic sanctions on Iran.
In response, Tehran has progressively reduced a number of its key commitments to an agreement that drastically limited its nuclear activities.
Britain, France and Germany on Tuesday announced they were starting the so-called dispute mechanism to try to bring Iran back into full compliance with its commitments under the accord.
During a sermon at Friday prayers in Tehran, Khamenei accused the "wicked" governments of Britain, France and Germany of "threatening Iran to take the nuclear issue to the (UN) Security Council."
Iran's top leader said the launch of the dispute mechanism was "done to overshadow" the killing of top Iranian general Qasem Soleimani in a US drone strike in Baghdad, and Iran's subsequent retaliation.
Last week, Iran fired a volley of missiles at US troops stationed in Iraqi military bases, wounding 11 American soldiers.
Khamenei accused the European governments of historic animosity towards Iran.
"These three countries are the ones that during the (Iran-Iraq war) helped Saddam Hussein as much as they could," he said, referring to the former Iraqi dictator and Iran's erstwhile foe.
"It has been proven now, after about a year, that they are, in the true sense of the word, America's lackeys, and these cowardly governments are waiting for the Iranian nation to surrender," he said.
"Even when they negotiate, their negotiations are tainted with deceit… those behind the negotiating table, those gentlemen, are the same as the terrorists at Baghdad airport" who killed Soleimani, he said.
"They cannot be trusted."