American Airlines cut its full-year profit forecast on Thursday as renewed U.S.-Iran fighting pushed oil prices higher again, adding to its fuel bill.

The carrier now expects an adjusted ‌loss of 65 cents per share to ​an adjusted profit of 65 cents per share, compared with its previous forecast ⁠of an adjusted loss of 40 cents ​to a profit of $1.10 per share.

Shares of the airline fell ⁠about 4% in premarket trading.

The move highlights how volatile fuel markets have complicated earnings forecasts for airlines, as renewed U.S.-Iran ‌fighting and reduced traffic through the ​Strait of Hormuz cloud ‌the outlook for oil and jet fuel costs. The strait carried ‌about a fifth of global oil and gas shipments before the war.

Jet fuel surged above $5 per ⁠gallon during the spring ‌before retreating sharply in ⁠June, following a truce between Washington and Tehran. Oil prices ⁠have ⁠climbed again since the fragile agreement collapsed in early July, renewing ‌upward pressure on airline fuel costs.

American paid an average of $4.05 per gallon for fuel in the second quarter, compared ‌with ​the approximately $4 per ‌gallon assumed in its April guidance. For the third quarter, it expects to pay $3.75 per gallon, ​based on the forward fuel curve as of July 21.