If you see a hobo polar bear, panic!

A bomb squad has been called in to take down a "hobo polar bear" that had commuters alarmed outside a train station in the US.

Passersby on the street first noticed the shabbily-dressed figure standing by a rubbish bin outside the Columbia Heights Metro station in Washington DC soon after daybreak, nbc4.com reports.

Huge crowds gathered to watch the scene while train services were halted before police gave the all-clear.

The local station was closed for almost two hours as the matter was investigated.

The bomb squad arrived hours later and tore the "bear" apart, revealing what appeared to be an elaborate costume and a great deal of stuffing.

Local bloggers immediately began circulating theories to explain its presence, with one believing the "bear" was most likely a Mark Jenkins art installation commenting on global warming.

Jenkins has left similar-looking street art in locations across the globe, ranging from man-horse hybrids to figures stuck upside down in rubbish bins.

"Did anyone see it move?" wrote blogger DCist.

Another theory was it was the same costume bear which had been seen around the US capital holding placards bemoaning climate change and other environmental issues.

Authorities are yet to give their own explanation for the incident.

Original article here.