SINGAPORE: Oil prices rose nearly 3 percent 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 were last up $1.50, or 1.8 percent, to $84.80 per barrel at 06:30 a.m. Saudi time, while US West Texas Intermediate crude rose $1.70, ​or 2.2 percent, to $79.84 a barrel.

Both contracts earlier rose more than $2 a barrel before paring some gains, while ​Brent had surged 9.6 percent in the previous session, its biggest daily gain since May ⁠2020.

Oil prices are now at their highest since the two countries signed a memorandum of understanding to end the war ​on June 17.

The US military carried out a third consecutive night of strikes against Iran on Monday, as US President Donald ​Trump reinstated a blockade of Iranian shipping and proposed charging a 20 percent fee to guard the Strait of Hormuz.