The UK has agreed to allow the United States to use British bases to launch strikes on Iranian sites targeting the Strait of Hormuz.
Prime Minister Sir Keir Starmer previously allowed US forces to use the bases only for defensive operations to prevent Iran firing missiles that put British interests or lives at risk.
On Friday, Downing Street said ministers approved an expansion of the targets to help protect ships in the strait – a vital oil shipping channel - and still on the basis of "collective self-defence".
A Downing Street spokesperson said of Friday's discussions by ministers: "They agreed that Iran's reckless strikes, including on Red Ensign vessels and those of our close allies and Gulf partners, risked pushing the region further into crisis and worsening the economic impact being felt in the UK and around the world.
"They confirmed that the agreement for the US to use UK bases in the collective self-defence of the region includes US defensive operations to degrade the missile sites and capabilities being used to attack ships in the Strait of Hormuz."
Downing Street added ministers want "urgent de-escalation and a swift resolution to the war".
The expansion comes after Iran's foreign minister warned the UK it views its choice to let the US use British bases as "participation in aggression".
www.bbc.co.uk/news/articles/c36rny6xgppo