The Canadian flag was mistakenly being raised upside down over the Peace Tower on Parliament Hill in Ottawa, July 8, 2011. (John Major/QMI Agency)

OTTAWA - For a moment, it looked like the Russians were coming.

The flag that flies atop the Peace Tower on Parliament Hill was flown upside down on Friday morning.

It took a minute for the rectangle to be righted and for calm to be restored.

Flying a flag upside down is an internationally recognized distress signal.

In this case the sergeant-at-arms, in charge of security on the Hill, assured QMI Agency that no invasion was imminent, and chalked it up to a public works mistake.