Article 53 3.

to the extent justified by a restriction to the use of that band based on the general interest objective provided in point (a) or (d) of Article 45(5);

in the case of unresolved cross-border coordination issues resulting in harmful interference with third countries, provided the affected Member State has, where appropriate, requested Union assistance pursuant to Article 28(5);

safeguarding national security and defence; or

force majeure.