PARIS, France — A crackdown on protests in Iran has killed at least 648 people, a rights group said on Monday, as Iranian authorities sought to regain control of the streets with mass nationwide rallies.

 

The government's call for rallies in support of the Islamic republic drew thousands on Monday, a turnout supreme leader Ayatollah Ali Khamenei hailed as proof that the protests -- which the authorities attribute to foreign interference -- had been defeated.

 

US President Donald Trump has repeatedly threatened to intervene militarily if Tehran killed protesters, with Press Secretary Karoline Leavitt saying on Monday that military options including air strikes were still "on the table", but "diplomacy is always the first option for the president".

 

More than two weeks of demonstrations initially sparked by economic grievances have turned into one of the biggest challenges yet to the theocratic system that has ruled Iran since the 1979 Islamic revolution ousted the shah.

 

Khamenei, in power since 1989 and now 86, said in a statement that Monday's pro-government rallies were a "warning" to the United States.

 

"These massive rallies, full of determination, have thwarted the plan of foreign enemies that were supposed to be carried out by domestic mercenaries," he said, according to state TV.

 

'Four-front war'

 

At Enghelab (Revolution) Square, parliament speaker Mohammad Bagher Ghalibaf told the crowd that Iran was fighting a "four-front war", listing economic war, psychological war, "military war" with the United States and Israel, and "today a war against terrorists" -- a reference to the protests.

 

Flanked by the slogans "Death to Israel, Death to America" in Persian, he vowed the Iranian military would teach Trump "an unforgettable lesson" if Iran were attacked.

 

But Trump said Sunday that Iran's leadership had called him seeking "to negotiate", and Leavitt noted public messages from Iranian authorities were "quite different from the messages the administration is receiving privately".

 

Foreign Minister Abbas Araghchi told a conference of foreign ambassadors in Tehran that Iran was "not seeking war but is fully prepared for war", while calling for "fair" negotiations.

 

Foreign ministry spokesman Esmaeil Baghaei said a channel of communication was open between Araghchi and Trump's special envoy for the Middle East Steve Witkoff despite the lack of diplomatic relations.

 

Reza Pahlavi, the US-based son of Iran's ousted shah who has been vocal in calling for protests, told CBS news the government was "trying to trick the world into thinking that (it) is ready to negotiate once again".

 

He said Trump was "a man that means what he says and says what he means" and who "knows what's at stake".

 

"The red line that was drawn has been definitely surpassed by this regime."

 

Tehran Governor Mohammad-Sadegh Motamedian insisted in televised comments that "the number of protests is decreasing".

 

Iranian state media has said dozens of members of the security forces have been killed, with their funerals turning into large pro-government rallies. The government has declared three days of national mourning for those killed.

 

The European Union has voiced support for the protesters and on Monday said it was "looking into" imposing additional sanctions on Iran over the repression of demonstrations.

 

The European Parliament also announced it had banned all Iranian diplomats and representatives from the assembly's premises.

 

The Iranian foreign ministry said it had summoned diplomats in Tehran representing France, Germany, Italy and the UK, demanding they "withdraw official statements supporting the protesters".

 

French President Emmanuel Macron, however, issued a statement later Monday condemning "the state violence that indiscriminately targets Iranian women and men who courageously demand respect for their rights".

 

Non-essential French embassy staff left Iran on Sunday and Monday, two sources with knowledge of the matter told AFP.

 

Tehran ally Russia, for its part, slammed what it called attempts by "foreign powers" to interfere in Iran, state media reported, in Moscow's first reaction to the protests.