Fujairah has issued a circular to this effect.
Following is from Abu Dhabi port authority, which at the moment is only prohibiting Qatar Flag vessels.
This is likely to change though.
Referring to the announced blockade on the State of Qatar, please be advised that the Petroleum Ports Authority management has not to-date received firm directives, however as an initial response to the announcement, and until further instructions, vessels flying the “Flag of Qatar” shall not be allowed entry into any of Abu Dhabi Petroleum Ports.
Please be guided accordingly.