He said the attempt by the United States to strengthen its force at Fort Sumter was clearly an act of aggression.

VOA: special.2009.07.23

Well, violations of the law of nature are an act of aggression.

违反自然法是一种侵略行为。

耶鲁公开课 - 公正课程节选

Poles still view the Red Army invasion as an act of aggression, especially the Katyn Forest massacre, in which some 22,000 Polish soldiers, police and intellectuals were murdered by Soviet forces in 1940.

VOA: standard.2009.09.01

Lebanon accused Israel of aggression and said the army would act to defend the nation's sovereign borders.

VOA: standard.2010.08.03