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(NEWSER) – A NATO summit today in Wales originally meant to focus on the ongoing Ukraine crisis will shift gears to include high-level discussions on the American- and British-led push to address ISIS, reports the New York Times.

President Obama and British PM David Cameron penned a joint letter in the Times of London today, and they don't mince words, writing, "If terrorists think we will weaken in the face of their threats, they could not be more wrong. Countries like Britain and America will not be cowed by barbaric killers."

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