At the time of writing, Brent crude was down 0.91% at $79.12 a barrel, while US West Texas Intermediate (WTI) crude had fallen 0.70% to $75.32 a barrel.
Lower crude prices reflected broader investor sentiment in early trading after Qatari and Pakistani mediators said the first round of negotiations between the US and Iran aimed at securing a final agreement to end the conflict had concluded with "encouraging progress".
A memorandum of understanding signed last week includes a commitment to reach a final agreement within 60 days, an end to fighting on "all fronts" - including in Lebanon - and the reopening of the Strait of Hormuz.
UK prime minister steps down, dragging on the pound
In the afternoon, market watchers turned their attention to the UK as Keir Starmer resigned from the pm post.
