U.S. Treasury yields were relatively unchanged on Friday after the U.S. said its naval blockade of Iranian ports could continue "indefinitely."

The yield on the 10-year U.S. Treasury note — the key benchmark for U.S. government borrowing — rose less than 1 basis point to 4.645%.

The 2-year Treasury note yield, which more closely tracks short-term Federal Reserve interest rate policy, fell more than 1 basis point to 4.129%. The longer-dated 30-year Treasury bond yield advanced 2 basis points to 5.231%.

One basis point is equal to 0.01%, and yields and prices move in opposite directions.

Friday's upward moves follow U.S. Treasury Secretary Scott Bessent's comments in an interview with Newsmax, in which he warned of fresh measures aimed at the "economic isolation" of Iran which "have never been seen."

Bessent's comments came after U.S. Defense Secretary Pete Hegseth told reporters U.S. forces could maintain an indefinite blockade of Iranian ports.

The producer price index, which measures what wholesalers pay for raw goods and materials, was flat month over month in July. Economists polled by Dow Jones expected an increase of 0.2%.

Thursday's print follows a tame reading on consumer inflation, with the consumer price index coming in line with economist expectations.

"US inflation data this week has been contained and very welcome for Treasuries," ING strategists wrote in a note Friday. "It absolutely eases higher rates pressure. But that pressure is far from gone. Real yields are higher and will likely remain so."

— CNBC's Hugh Leask also contributed to this report.