[Video transcript]

Sana's streets packed with protesters.

They're incensed by a wave of US and British strikes on dozens of Houthi targets in Yemen, launched in retaliation for attacks on shipping in the Red Sea.
 
(Abdulrahman al-Ahnoumi, Houthi media official) 
"This rally is first to condemn the aggression against the Republic of Yemen last night. It is also a message to Britain and the United States of America in particular, that they will pay a heavy price for this aggression. These crowds today authorize the leader of the revolution and authorize the military leadership to respond to the aggression at high levels at sea and on land."

But the US and UK say the strikes, which hit military targets, were acts of self-defence.

Houthi rebels — who are backed by Iran — have been targeting ships in the Red Sea for weeks, with the group releasing this footage in November of its fighters appearing to seize a vessel.  It claims the attacks are in response to Israel's war in Gaza against Hamas — whom the US, EU and other countries have labeled a terrorist organization.

British Prime Minister Rishi Sunak, who is currently visiting Ukraine, said the UK had no choice but to respond.

(Rishi Sunak, British Prime Minister) 
"Well, over the last month we've seen a significant increase in the number of Houthi attacks on commercial shipping in the Red Sea. That's putting innocent lives at risk, it's disrupting the global economy and it's also destabilizing the region, and in that time we've also seen the single biggest attack on a British navy warship in decades. Now, it's clear that that type of behaviour can't carry on." 

The big question now is what this could mean for the war in Gaza and the wider region — with the world bracing for a response from the Houthis and those who support them.