The Canadian delegation to Nato has come up with this response to reports that Russian troops entered Ukraine "by mistake".
The sarcastic tweet, which attracted claims that Canada has "trolled" Russia, has been re-tweeted more than 17,000 times.
On Tuesday, an unnamed Russian security source was quoted as saying the incursion was a "mistake" - a claim contradicted by Ukraine which says the troops have attacked the eastern town of Novoazovsk.
Were the Russians -as Barack Obama claims - weighed down by sanctions, or where the Ukrainians looking to cut their losses?
The new president of the European Council could be "very important" for David Cameron.