It is a violation of international law, and a threat to friendly international relations, for a coastal state to engage in any of the following acts which interfere with rights of innocent passage: (a) to hamper innocent passage through the territorial sea; (b) to fail to give appropriate publicity to dangers to navigation, of which it has knowledge, within its territorial sea; (c) to discriminate amongst foreign ships in the effective exercise of the rights of innocent passage; (d) to suspend the innocent passage of foreign ships through straits which are used for international navigation between one part of the high seas and another part of the high seas or the territorial sea of a foreign state.