U.S. diesel prices hit a record on Friday.

They passed $6 a gallon on average.

The national average is nearly $6.06.

That is up from $5.85 last week and about $3.71 a year ago, according to AAA.

The rise follows Washington's war with Iran.

The war has disrupted the world's fuel flow.

Diesel powers many freight and delivery networks.

So higher prices mean more costly transport for everyday goods.

Some businesses have already added fees on online orders and mail packages.

Groceries may see the biggest impact.

This is especially true for foods like meat and produce that must be moved and restocked often.

Diesel and gasoline prices follow crude oil, which has risen again.

This week, Brent and U.S. crude both passed $100 a barrel.

This is the first time in months as fighting grew worse.

President Donald Trump said oil prices likely won't fall until after November's midterm elections.

Diesel is now over 60% higher than before the U.S. and Israel attacked Iran in late February.

At that time, the average was about $3.76 per gallon.

The IEA reported Friday that Saudi oil production fell to a three-decade low last month.

This was due to Houthi attacks.

It also noted that Ukrainian attacks have nearly halted Russia's product exports.