Sending blockade-busting ships is a violation of International Law:
San Remo Manual on International Law Applicable to Armed Conflicts at Sea, 12 June 1994.
Part IV: Methods and Means of Warfare at Sea.
Section II: Methods of Warefare
Blockade
98. Merchant vessels believed on reasonable grounds to be breaching a blockade may be captured. Merchant vessels which, after prior warning, clearly resist capture may be attacked.
