Russia's defense ministry said Monday that it will treat U.S.-led coalition planes west of the Euphrates in Syria as targets after the U.S. downed a Syrian jet over the weekend, bringing an end to the agreement between the U.S. and Moscow, reports FT.

The no-fly zone demanded by Russia: Key cities like Aleppo and Damascus would be out of bounds for coalition aircraft. Most Kurdish and ISIS territory would not. (Go deeper with this map by Axios' Lazaro Gamio.)

Why it matters: The incident is the first time the U.S.-led coalition has shot down a Syrian plane since the beginning of the country's civil war six years ago. Moscow denounced the action as a violation of international law and has reportedly suspended its incident-prevention hotline with the U.S. in Syria in retaliation, per AFP.