Qassem Suleimani, who was killed in a US drone strike in Baghdad, was widely considered to be the most powerful man in Iran after the supreme leader, Ayatollah Ali Khamenei – and Iran's leading military figure.

Suleimani’s assassination has plunged the Middle East into a crisis that seems likely to lead to further escalation between Washington and Tehran. The Guardian's Middle East correspondent Martin Chulov examines what motivated Donald Trump to order the assassination