ISTANBUL 

Anti-war protests have been held in Greece and the UK after the US and Israel launched an attack on Iran Saturday.

Protesters gathered outside the US Embassy in Athens on Sunday to protest the US and Israeli attacks, according to broadcaster ERT.

Demonstrators held a central banner reading "They are wreaking havoc in the Middle East. Greece out of the massacre."

They also chanted slogans such as "The people will provide a way out of the war, imperialism is not invincible."

Attended by various associations and organizations, the protest also had people carrying Palestinian and Iranian flags.

On Saturday, people also gathered in London to protest against the US-Israeli actions.

During the protest supported by the Campaign for Nuclear Disarmament group, people chanted slogans such as "Hands Off Iran!" and "No More War!"

Since Saturday morning, Israel and the US have carried out strikes on multiple Iranian cities, killing the supreme leader and many other top security officials.

Israel said the operation was meant to remove the "existential threat" while US President Donald Trump announced "major combat operations" against the Iranian "regime."

Iran, in response, launched drone and missile attacks on Israel and US assets in the region that prompted many Gulf states to shut their airspace.

Iranian authorities pledged revenge after confirmation of Khamenei's death, declared a 40-day mourning period and an interim council was named until a successor is chosen.