US president declares additional economic sanctions on Iran but attempts to de-escalate crisis

• Iran crisis: a visual guide to the latest developments
• Iran launches missiles at Iraq airbases hosting US and coalition troops

8.33pm GMT

The quartet of US secretary of state Mike Pompeo, the still relatively new defense secretary Mark Esper, chairman of the US joint chiefs of staff Mark Milley and the historically-controversial CIA director Gina Haspel strode across Capitol Hill today to brief members of Congress on the Iran issues.

There is some difference of perspective on how effective the briefing was.

Rep Mark Meadows says the briefing for lawmakers was “compelling and decisive” and left “little doubt” that the president made the right call in killing Qasem Soleimani and there was “clear and present danger.”

Meadows says Director Haspel was very “clear and articulate” that there was an “imminent threat” from Qasem Soleimani. “This general’s absence will not be easily replaced,” he adds and says it will take months if not years to fill the gap Qasem Soleimani leaves.

House Foreign Affairs Committee Chairman Eliot Engel said the theme of the Iran briefing "was the administration saying trust us."

"I’m not sure who I trust or what I trust. We’ve been told so many different things that really just bother me."

GOP KY Sen Paul: I think sanctions have actually pushed Iran away from the negotiating table and made it less likely to have a diplomatic solution..I did just speak to the President moments ago, I do believe that the President honestly does not want another war in the Middle East

8.11pm GMT

British prime minister Boris Johnson and his Canadian counterpart, Justin Trudeau, had a telephone call with each other earlier in which they discussed the need for urgent de-escalation on all sides in the US-Iran crisis following Iranian missile attacks on military bases housing US troops in Iraq overnight, a spokesperson for Johnson said.

The leaders also discussed working together, and with international partners, to ensure Iran is prevented from acquiring a nuclear weapon.