The US moved quickly to justify the aerial attacks as legal. The US ambassador to the United Nations, Samantha Power, told Secretary-General Ban Ki-moon in a letter that such attacks were permitted under a fundamental principle in the UN Charter that gives countries the right to defend themselves, including using force on another country‘s territory when that country is unwilling or unable to address it.

„The Syrian regime has shown that it cannot and will not confront these safe havens effectively itself,“ the letter states.