Athens: Greek police have arrested two teenage girls on suspicion of stabbing to death an 80-year-old man during a euro10 (US$12) robbery.

Police said Monday that the two girls, aged 15 and 16, are accused of repeatedly stabbing the man in the chest and abdomen after he began to call for help when they threatened him with a knife.

The 80-year-old had allowed the teenagers into his home in Serres in northern Greece, where he lived alone.

Authorities say the girls stole euro10 euros (US$12) from the man's wallet after killing him on Sunday afternoon.

Police said the girls were detained as suspects and later admitted to the fatal robbery. They face charges of murder.

Authorities have not released the identities of the victim or the two girls.