A dog believed to have survived the tsunami and then three weeks at sea was rescued by the Japanese Coast Guard in northern Japan.

Coastguards spotted the dog on the floating roof of a house that had been washed out to sea, about 1.8 kilometers (1.1 miles) from the coast of Kesennuma in northern Japan.

The dog had evaded capture for several hours as it scrambled over the large tract of floating rubble.

However, once rescued, it captured the hearts of the coast guards. Initially shaken by the experience, it quickly seemed to get used to its new home on the coast guard vessel, and licked its rescuers' hands.

The crew could only speculate who the dog belonged to as they could not find a name tag or ID on the collar. The Japanese broadcaster NTV said the the coast guard had hoped the pet would lead them to the owner.

It was a rare piece of good news as Japan's rescue services, along with US forces, launched a three day operation to search for and recover the 18,000 people still missing and now presumed dead, after the earthquake and subsequent tsunami three weeks ago.