The official number of dead and missing after the devastating earthquake and tsunami that flattened Japan's northeast coast a week ago has topped 16,600, with 6,405 confirmed dead, police said Friday.

The number of people unaccounted for following the March 11 twin disasters increased to 10,259, the National Police Agency said in its latest update.

A total of 2,409 people were injured.

The toll has increased steadily in recent days, and reports suggest it could eventually be much higher.

The mayor of the coastal town of Ishinomaki in Miyagi prefecture said late Wednesday that the number of missing there was likely to hit 10,000, Kyodo News reported.

On Saturday, public broadcaster NHK reported that around 10,000 people were unaccounted for in the port town of Minamisanriku in the same prefecture.

Amid a mass rescue effort there were grim updates indicating severe loss of life along the battered east coast of Honshu island, where the monster waves destroyed or damaged more than 55,380 homes and other buildings.