Reuters: US, Ukraine discuss risk of escalation amid weapons provisions.

As western partners equip Ukraine with increasingly sophisticated, longer-range weapons, the U.S. spoke of the danger of escalation should Ukraine hit Russia’s interior, reports Reuters, citing unnamed U.S. and diplomatic officials. “We have concerns about escalation and yet still do not want to put geographic limits or tie their (Ukraine's) hands too much with the stuff we're giving them," a U.S. official reportedly said.