TEHRAN — In Tehran’s largest anti-American rally in years, tens of thousands of demonstrators joined Monday in chants of ‘‘death to America’’ as hard-liners directed a major show of resolve against President Hassan Rouhani’s outreach to Washington more than a generation after crowds on the same streets stormed and occupied the US Embassy.
Such American-bashing protests occur every year outside the former embassy compound to mark the anniversary of the 1979 takeover following the Islamic Revolution.
But the latest demonstration had a dual purpose of sending the boldest warning yet to Rouhani’s government over whether it can expand dialogue with the United States or offer the concessions needed to possibly settle the nuclear impasse with the West.
‘‘Fighting the global arrogance and hostile policies of America is the symbol of our national solidarity,’’ said Saeed Jalili, who lost to Rouhani in June’s election and was replaced as the country’s top nuclear negotiator.
The choice of Jalili as the main speaker to the crowd showed how deep the rifts reach in Iran.
Jalili is a leading voice of dissent over Rouhani’s overtures to Washington, but he is also a senior adviser to Supreme Leader Ayatollah Ali Khamenei, who has given critical support to Rouhani’s initiatives. The growing tensions have left Khamenei — the ultimate decision-maker in Iran — in the unusual role of domestic diplomat.
He had stood by Rouhani in apparent hopes that the nuclear talks and outreach can ease Iran’s isolation from the West and roll back painful sanctions over Tehran’s nuclear program. At the same time, he cannot ignore Rouhani’s critics.
He seeks a middle ground built around his comments that America remains untrustworthy but Iran is strong enough to pursue talks and exchanges.
Another key test comes later this week when nuclear talks resume in Geneva between Iran and six world powers including the US envoys.
Negotiators left last month’s session expressing hope that Rouhani’s election — and full backing from Khamenei — could lead to progress in closing the gap between Western fears that Iran could eventually produce nuclear weapons and Iran’s claims that it only seeks reactors for energy and medical research.
Any stumbles in the talks, however, will probably spark greater protest backlash from hard-liners such as the Revolutionary Guard and its vast paramilitary network.
In a symbolic show of force, they slammed back at appeals by Rouhani’s backers to drop the longstanding chant of ‘‘death to America’’ following the groundbreaking exchanges in late September during the annual UN General Assembly — which included a call from President Obama to Rouhani as the Iranian president headed to the airport.
Ties between the two countries were severed after the embassy siege, which began a hostage crisis with 52 people held for 444 days.
White House spokesman Jay Carney acknowledged the process would not be easy.
‘‘As the president has said, the history of mistrust between the United States and the Islamic Republic of Iran is deep and it will not be erased overnight.’’
Asked about the demonstrations and calls of ‘death to America’ in Tehran on this anniversary, Carney said: ‘‘We believe that the vast majority of Iranians would prefer a better relationship with the West and would prefer the benefits of that better relationship with the West, including economic benefits of rejoining the international community to the current status quo.’’
Jalili said the chant ‘‘death to America’’ — which rang out strongly among the more than 50,000 people outside the former embassy — is a symbol.
‘‘It’s not death to American people, but it’s against a portion of Americans who support oppressive policies in the world. If we say ‘death to America,’ it is death to megalomania. ‘Death to America’ means death to think tanks that work for the destruction of nations.’’
Protester Reza Farahbakhsh called the rally ‘‘more spirited’’ than recent years, when crowds dwindled to several thousands and had to be padded with schoolchildren brought by bus.
‘‘Some people said, ‘Let’s not chant death to America this year, it is not good for us,’’’ he said. ‘‘The world must see this.’’