The US has begun a new wave of strikes against Iran after reimposing a naval blockade of Iranian ports, while Iran is threatening to shut off more regional energy ‌exports.

The strikes mark the latest escalation of attacks and counterattacks launched by the two sides as they vie for control of the Strait of Hormuz, which carried about a fifth of global oil and gas shipments before the war.

“At 3pm ET today, U.S. forces launched operations for a second wave of strikes today against Iran,” US Central Command said on Thursday.

The fresh wave followed a daytime raid that followed a fourth night of US airstrikes.

Late on Tuesday the US military said it had hit dozens of military targets near the Strait of Hormuz and Iranian ⁠coastal areas in strikes lasting seven hours.

In response, Iran’s ‌Islamic Revolutionary ​Guard Corps said on Wednesday it had struck US military targets in the region, including in Bahrain, ​Kuwait and ‌Jordan.

It also threatened on Wednesday to shut off more regional energy exports, saying the US “must brace ​for the closure of all other export corridors that benefit the US and its allies”.

Meanwhile, when asked by a reporter whether he was giving Iran a deadline before bombing bridges, President Trump said “they better behave”.

“I don’t like giving deadlines, but they pretty much know—they know the story.”

The US has said Iran had attacked seven commercial ships in the past week, leading to ​nearly ​a dozen crew members being killed, missing ​or injured.

Oil prices extended gains by about one per cent on Wednesday, after settling on Tuesday on a new one-month high.

An interim ​ceasefire deal in the conflict signed last month was meant to lead to further negotiations ​and a permanent truce, but ⁠a return to talks has faltered.

—with AAP