TOKYO - Hiromitsu Shinkawa was pushed out to sea while he clung to the roof of his home after a tsunami swept away his wife. For two days, he drifted off Japan's northeastern coast, trying to get the attention of helicopters and ships that passed by -- to no avail.

Finally, on Sunday, a Japanese military vessel spotted the 60-year-old waving a red cloth. He was about 15 kilometres (about 10 miles) offshore from the earthquake-ravaged city of Minamisoma, said Yoshiyuki Kotake, a Defence Ministry spokesman.

Shinkawa told his rescuers that the tsunami hit as he and his wife returned home to gather some belongings after Friday's quake. His wife was swept away, Kotake said.

"Several helicopters and ships passed by, but none of them noticed me," he was quoted by another defence agency spokesman, who refused to be identified by name, as saying.

Japanese troops used a small boat to pluck him from the ocean.

Military officials said Shinkawa was lucky that mild weather and relatively calm seas enabled him to stay afloat for nearly two days, the Kyodo news agency reported.

"I thought today was the last day of my life," it quoted him as saying.