International flight tickets issued in April could cost more than 100,000 won ($75) higher than those purchased this month for the same routes, as Korean Air and low-cost carriers face mounting pressure from surging aviation fuel costs following the U.S.-Israeli strikes on Iran, according to data and industry officials Sunday. The anticipated increase is tied to a sharp rise in fuel surcharges — additional fees to cover fluctuating fuel costs. The figure for April is set to be announced Monday. As the Middle East crisis shows signs of becoming prolonged, international oil prices have climbed steeply, raising concerns that fuel surcharges attached to airline tickets will also sharply jump next month. Airlines adjust fuel surcharges monthly based on international aviation fuel prices. For Korean Air, the surcharge currently ranges between 13,500 won and 99,000 won for tickets issued in March. The upper range is an increase of around 30 percent from the previous month. Asiana Airlines' fuel surcharge is also increasing. The surcharge in March soared to as high as 78,600 won, up 19 percent