hmmm
Due to existing aid relations between the United States and Israel, the latter is required to notify and seek permission from Washington prior to selling any fighter jets to a third party.
Practically, the F-16 deal with Croatia is dead and we don’t think it is possible to get an agreement that will reconcile the U.S. conditions and the Croatian demands in the tender,” the official stated, adding that the rejection has embarrassed Israel, who is now required “to apologize to Croatia for the deal falling apart.”
https://www.telesurenglish.net/news/US-Mattis-Blocks-US500M-Israel-F-16-Sale-Before-Resigning-20181229-0003.html
"adding that the rejection has embarrassed Israel"