Tensions in the Middle East continue to escalate as Iran has vowed retaliation over US military strikes on its nuclear facilities while US President Donald Trump has openly hinted at possible regime change in Tehran.

Iranian Supreme Leader Ali Khamenei, in his first remarks since the US joined Israel’s attacks on Iran, promised to punish “the Zionist enemy”. His statement comes amid ongoing exchanges of strikes between Israel and Iran.

US President Trump questioned the future of Iran’s leadership. “If the current Iranian regime is unable to make Iran great again, why wouldn’t there be a regime change?” Trump said, fuelling speculation about Washington’s broader goals following the strikes.

Iran’s ambassador to the United Nations has accused the US of "waging war" under an "absurd pretext" after American forces hit three key Iranian nuclear sites—Fordo, Natanz, and Isfahan.

Oil prices have surged in response to the developments. US Secretary of State Marco Rubio has urged China to apply pressure on Tehran to prevent the closure of the strategic Strait of Hormuz, a critical route for global energy shipments.

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The US State Department has issued a worldwide alert for American citizens, warning of possible retaliatory attacks following the escalation.

Uncertainty remains over the extent of damage to Iran’s nuclear programme.

President Trump has claimed the strikes effectively neutralised Iran’s nuclear ambitions, saying the US action took "the 'bomb' right out of their hands".

However, the UN’s nuclear watchdog has stated it cannot yet determine the current situation at the Fordo plant.

Despite the US strikes, Israel and Iran have continued trading attacks over the past 24 hours, intensifying fears of a wider conflict.

According to Iranian authorities, more than 400 people have been killed and at least 3,056 others wounded since Israel launched its assault on June 13. On the Israeli side, at least 24 people have reportedly been killed in retaliatory Iranian strikes.

With inputs from Al Jazeera, BBC