President Donald Trump has again extended a waiver that allows foreign ships to carry oil and other commodities between US ports, as the war on Iran continues to disrupt energy flows and elevate costs, AFP reports.

The 90-day extension of relief from the Jones Act — which requires cargo between US ports to move on US vessels — comes shortly before an earlier waiver was due to expire in mid-August.

But the scope covered is narrower this time, focusing more on the transport of energy, a White House official confirmed.

“Today, the Trump Administration issued a 90-day extension to the Jones Act waiver to ensure our military and key industries maintain uninterrupted access to critical resources,” said White House spokeswoman Taylor Rogers.

“Data shows the waiver has driven a significant increase in domestic deliveries of essential products such as gasoline, diesel, and jet fuel,” she added.