A man suspected of organizing a series of robberies across Japan through social media is detained in the Philippines.

Philippine Justice Secretary Jesus Crispin Remulla told NHK on Friday that Japanese police believe the man, called Watanabe, may also go by "Luffy," the name of a suspect behind the robberies.

The man is being held at the immigration bureau's Bicutan Detention Center in the greater Manila region.

Remulla said another man, who is believed to be a member of a group instructed by Luffy, is also being detained.

The group is suspected of carrying out the robberies, one of which resulted in the death of an elderly woman in Tokyo.

The minister said he will consider whether to hand over the two men to Japan if so requested by Japanese police.