Oil prices rose 2% on Tuesday to their highest in four weeks, as the US reimposed its naval blockade of Iran while the two countries stepped up attacks in the Strait of Hormuz, heightening uncertainty about energy flows. Brent crude futures climbed $1.68, or 2%, to $84.98 per barrel by 0051 GMT, while US West Texas Intermediate crude rose $1.65, or 2.1%, to $79.79 a barrel. Brent crude sur