broke out

check out the passive voice in this lede:

Six American soldiers were killed and 11 others wounded in Iraq on Monday, bringing the death toll of U.S. soldiers killed in Iraq to about 3,400 since the U.S.-led invasion broke out in 2003, the U.S. military said on Tuesday.

sometimes invasions just break out all of a sudden. like acne. there's nothing you can do about it, even if you try your best to avoid greasy foods. why just last saturday i was walking down the street in ardmore and suddenly i was surrounded by imperial storm troopers. i hate when that happens.