Shipping lanes Could the Red Sea crisis risk sparking a wider conflict?

So far, the war in Gaza prompted by Hamas's attack on 7 October has not precipitated the nightmare scenario - a wider Middle East conflict drawing in the US and Iran. But that risk appears to be becoming more serious.

- Archie Bland

The centre of the danger is in the Red Sea, where Houthi forces based in Yemen and backed by Iran have been attacking freighters with real or perceived links to Israel.

The US has offered protection to shipping travelling through the region, assembling a multinational naval coalition. But President Joe Biden has said he wants to avoid direct military confrontation with the Houthis for fear of triggering an escalation.

Last Sunday, US naval forces crossed that line for the first time, killing all crew on three Houthi boats that had been attacking a container ship. Early this week, as Tehran rejected calls from Washington and London to end its support for the Houthis, an Iranian destroyer sailed into the Red Sea.

Meanwhile, the UK and US were considering a warning about strikes on military installations in Yemen.

How did the crisis begin?