Iran said Monday that a US attack of any scale would spur the Islamic republic to respond "ferociously", after President Donald Trump said he was considering limited strikes against the country.

Iran held annual military drills with Russia on Thursday as a second American aircraft carrier drew closer to the Middle East, with both the United States and Iran signaling they are prepared for war if talks on Tehran’s nuclear program fizzle out.

Iranian President Masoud Pezeshkian confirmed on Tuesday that he had ordered the start of nuclear talks with the United States, after his counterpart Donald Trump threatened "bad things" if no deal was reached.

Fatemeh Aman explains why extreme violence does not signal collapse, and why outside pressure often strengthens the system it seeks to break.

The Indian Foreign Ministry said on Friday that it “remains engaged” with Washington over the port of Chabahar in Iran, which has been sanctioned by the US.

Saudi Arabia has informed Iran that it will not allow its airspace or territory to be used for any military action against Tehran. The message comes as US-Iran tensions rise, with Washington warning of possible strikes and Iran threatening retaliation.

A US military attack on Iran is “imminent,” and could come within mere hours, Reuters has claimed, citing anonymous sources.

Over two weeks of protests mark the most serious challenge in years to Iran's theocratic leadership in their scale and nature but it is too early to predict the immediate demise of the Islamic republic, analysts say.

US President Donald Trump said Sunday that Iran's leadership had called him seeking "to negotiate" after he repeatedly threatened to intervene militarily if Tehran killed protesters.

The US and Israel are meddling in the unrest shaking Iran, the country’s president, Masoud Pezeshkian, said in a televised interview on Sunday.

Iran's Supreme Leader Ayatollah Ali Khamenei has called anti-government protesters "troublemakers" who are trying "to please the president of the US".

Iranians took to the streets in new protests Friday to press the biggest movement against the Islamic republic in more than three years, as authorities sustained an internet blackout as part of a crackdown that has left dozens dead.