"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.
Thousands had gathered inside a large prayer hall in central Tehran and packed the area and streets outside the building, chanting "Death to America".
Khamenei's sermon comes at a tumultuous moment for Iran, which had seemed headed for conflict earlier in January after Soleimani was killed on January 3 outside Baghdad airport, prompting retaliatory strikes against Iraqi bases housing US troops. As Iran braced for a counterattack, the Revolutionary Guard shot down a passenger plane shortly after it took off from Tehran's worldwide airport last week, mistaking it for a US cruise missile.
Iran's supreme leader said on Friday that even though the accidental downing of the Ukrainian airliner was a "bitter" tragedy, it should not overshadow the "sacrifice" of General Qassem Soleimani, commander of the elite "Quds" force, killed in a U.S. drone strike.
Iran's supreme leader called the accidential downing of a Ukrainian airliner a "bitter" tragedy Friday but said it should not overshadow the "sacrifice" of a top commander killed in a USA drone strike. He conceded nothing to the demands of the protesters that includes accountability for the Iranian Islamic Revolutionary Guards Corps (IRGC) shooting down a Ukrainian passenger plane, killing 176 people, 147 of whom held Iranian citizenship.
Anti-government protests have erupted across Iran over the incident, and the country is facing growing global pressure. Khamenei said the strike had dealt a "blow to America's image" as a superpower. He said Iran's enemies had seized on the crash to question the Islamic Republic, the Revolutionary Guard and the armed forces. Khamenei said his "heart burned" for the victims of the crash, but he accused Iran's enemies of seeking to exploit the tragedy to bury the United States' assassination of Iranian military leader General Qassem Soleimani, The New York Times reported.
And Khamenei warned that US sanctions imposed in a row over its nuclear program would not make Iran yield.
The Trump administration is dragging the United States into a war with Iran that could engulf the whole region and could quickly turn into a global conflict of unpredictable scope and the gravest consequences.
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. "If you do stand with the Iranian people it is because you want to stick your poisoned dagger into the back of the Iranian nation".
Khamenei mocked those efforts, dismissing "these American clowns who falsely and despicably say that they are standing with the Iranian people".
He said Iran was ready to negotiate, but not with the United States. Of course you haven't done that yet and you won't be able to do anything.
Earlier in the day President Hassan Rouhani emphasized in a televised speech that Iran "is working daily to prevent military confrontation or war", and maintained that a dialogue with the world was still "possible".
US President Donald Trump has warned Iraq that if the US exits their country, they will be ruined.