The EU is "looking into" imposing additional sanctions on Iran over the repression of protests convulsing the country, the bloc said.
"We stand ready to propose new, more severe sanctions following the violent crackdown on protesters," EU spokesman Anouar El Anouni said.
US President Donald Trump has said the United States may meet Iranian officials and is in contact with the opposition amid escalating unrest in Iran.
He is weighing a range of strong responses, including military options, to a violent crackdown on protests that are posing one of the biggest challenges to clerical rule since the 1979 Islamic Revolution.
"We are ready for war but also for dialogue," Iranian Foreign Minister Abbas Araqchi said in a briefing to foreign ambassadors in Tehran via English translation.
Mr Trump had warned Iran's leaders that the US would attack if security forces opened fire on protesters.
US-based rights group HRANA said that it had verified the deaths of 490 protesters and 48 security personnel, with more than 10,600 people arrested.
Iran has not given an official toll and the tallies cannot be independently verified.
Mr Trump said that Iran called to negotiate its nuclear programme, which Israel and the US bombed in a 12-day war in June.
"Iran wants to negotiate, yes. We might meet with them. A meeting is being set up, but we may have to act because of what is happening before the meeting, but a meeting is being set up. Iran called, they want to negotiate," he told reporters on Air Force One.
Mr Trump is to meet senior advisers tomorrow to discuss options for Iran, a US official said.
The Wall Street Journal reported that options included military strikes, using secret cyber weapons, widening sanctions and providing online help to anti-government sources.
"The military is looking at it, and we're looking at some very strong options," Mr Trump said.
Iranian Parliament Speaker Mohammad Baqer Qalibaf warned Washington against "a miscalculation".
"Let us be clear: in the case of an attack on Iran, the occupied territories (Israel) as well as all US bases and ships will be our legitimate target," said Mr Qalibaf, a former commander in Iran's elite Revolutionary Guards.
Repression and violence in Iran must end - Martin
Taoiseach Micheál Martin said that Iranians had the right to demonstrate and repression of people must end.
"I strongly condemn the brutal and violent suppression of protesters that has left hundreds of civilians dead in Iran over recent days," he said in a post on X.
"The people of Iran have a fundamental right to peaceful protest and freedom of expression.
"The repression must end. I urge the authorities in Tehran to uphold the rights of all their citizens.
"The violence must stop, the curtailing of basic freedoms must end, and dialogue begin at once."
Yesterday, Minister for Foreign Affairs Helen McEntee said that she was "deeply concerned" by developments in Iran.
She said she was in contact with the Embassy of Ireland in Tehran and with EU partners.
"I call on the Iranian authorities to refrain from any further violence, to restore communications, engage with demonstrators about their grievances and to uphold the fundamental rights of all Iranians."
The protests in Iran began on 28 December in response to soaring prices, before turning against the clerical rulers who have governed since the Islamic Revolution.
Iranians, who are struggling to make ends meet, have grown increasing resentful of the powerful Revolutionary Guards, whose business interests including oil and gas, construction and telecommunications are worth billions of euro.
State TV aired live footage of large crowds attending a funeral procession for security forces killed in Shahrud and pro-government demonstrations in cities such as Kerman, Zahedan and Birjand, held "in condemnation of recent terrorist events".
It also relayed calls from various senior officials inviting people to take to the streets today.
Iranian authorities accused the US and Israel of fomenting trouble and called for the nationwide rally to condemn "terrorist actions led by the United States and Israel," state media reported.
The situation in Iran is "under total control" after violence linked to protests spiked over the weekend, Mr Araqchi said.
He added Mr Trump's warning against Tehran of action should protests turn bloody had motivated "terrorists" to target protesters and security forces in order to invite foreign intervention.
The flow of information from Iran has been hampered by an internet blackout since Thursday.
Mr Trump said that he would talk to businessman Elon Musk about restoring internet access in Iran through his Starlink satellite service.
Footage posted on social media on Saturday from Tehran showed large crowds marching at night, clapping and chanting.
The crowd "has no end nor beginning," a man is heard saying.
Authorities declared three days of national mourning "in honour of martyrs killed in resistance against the United States and the Zionist regime," according to state media.
Three Israeli sources, who were present for Israeli security consultations over the weekend, said Israel was on a high-alert footing for the possibility of any US intervention.
Israel and Iran fought a 12-day war in June 2025, which the US briefly joined by attacking nuclear installations.
Iran retaliated by firing missiles at Israel and an American air base in Qatar.
While Iranian authorities have weathered previous protests, the latest have unfolded with Tehran still recovering from last year's war and with its regional position weakened by blows to allies such as Lebanon's Hezbollah since the 7 October 2023 attacks against Israel.
Iran's unrest comes as Mr Trump flexes US muscles internationally, having ousted Venezuelan leader Nicolas Maduro, and discussing acquiring Greenland by purchase or force.
Alan Eyre, a former US diplomat and Iran expert, thought it was unlikely the demonstrations would topple the establishment.
"I think it is more likely that it puts these protests down eventually, but emerges from the process far weaker," he said, noting that Iran's elite still appeared cohesive and there was no organised opposition.
Mr Trump, posting on social media on Saturday, said: "Iran is looking at FREEDOM, perhaps like never before. The USA stands ready to help!!!"
