United will cut interline agreements with Gulf Airlines from May 5 over its stance that the Gulf Airlines are subsidised by their governments.

An internal company memo was first leaked to the press and picked up by Skift, which says the airline will cut ticketing and baggage arrangements with Emirates, Qatar Airways, Saudia, Royal Jordanian and Fly Dubai. The cancellations are due to go into effect from 5 May.

US airlines have been in an open dispute with the Gulf’s airlines, Emirates, Etihad and Qatar in particular, saying that they are state-subsidised and benefit from access to funds that tilts numbers to their advantage. The Gulf’s airlines have rejected the allegation.

Airlines from both regions have also been trading jabs and more at each other over the past few months.

Emirates, Qatar Airways and Royal Jordanian were among the first to take to social media to poke fun at United Airlines over its mistreatment of a passenger on an overbooked flight. Emirates went as as far pointing to United CEO Oscar Munoz’s previous comments about the airline in March when he had said, “Those [Gulf] airlines aren’t airlines.”

Qatar Airways CEO Akbar al Baker has also spoken about US airlines, calling them “wicked” and “swindlers” at the Arabian Travel Market last month.

The big three US airlines, United, Delta and American, have been lobbying US President Donald Trump against Gulf Airlines, receiving promises of “a phenomenal tax aid.”

It has been speculated that the US’ laptop ban on flights from the Middle East is linked to the US carrier cause.