Qasem Soleimani: 'This will escalate an already volatile situation'

General Qasem Soleimani, the head of the Iranian Revolutionary Guards' elite Quds Force, has been killed by US forces in Iraq.

Iran's Foreign Minister, Javad Zarif, called the attack an "act of international terrorism", tweeting that the US "bears responsibility for all consequences of its rogue adventurism."

The Pentagon said in a statement: "This strike was aimed at deterring future Iranian attack plans. The United States will continue to take all necessary action to protect our people and our interests wherever they are around the world."

Chief international correspondent Lyse Doucet explains the significance of the attack.