There was a time when the opinion of Britain Foreign Secretary mattered in Middle Eastern affairs but, unfortunately, that time has passed. I don't think Israel or Iran care what Britain thinks and I'd wager that Britain isn't interested in anything beyond a strongly-worded letter to any side.
In any case, she said Iran and Israel must show restraint and de-escalate immediately.
In terms of markets, S&P 500 futures are down 0.6% and Nasdaq futures are down 0.7%, adding to Friday's rout.