Related Rule
Ecuador
Practice Relating to Rule 29. Medical Transports
Section A. Respect for and protection of medical transports
Ecuador’s Naval Manual (1989) states:
Medical vehicles … may not be deliberately bombarded. Belligerents are required to ensure that such medical facilities are, as far as possible, situated in such manner that attacks against military targets in the vicinity do not imperil their safety. 
Ecuador, Aspectos Importantes del Derecho Internacional Marítimo que Deben Tener Presente los Comandantes de los Buques, Academia de Guerra Naval, 1989, § 8.5.1.4.
The manual qualifies “deliberate attack upon … medical vehicles” as a war crime. 
Ecuador, Aspectos Importantes del Derecho Internacional Marítimo que Deben Tener Presente los Comandantes de los Buques, Academia de Guerra Naval, 1989, § 6.2.5.