Greece's foreign ministry on Sunday said that a Greek hostage abducted by a Nigerian Islamist group was likely dead, as was claimed by the kidnappers.
"The available information suggests that the Greek citizen abducted in Nigeria alongside six nationals of other countries is dead," the ministry said in a statement.
"The foreign minister has communicated with the victim's mother to express his grief," it said.
The ministry declined to give further information on the hostage.
Nigerian Islamist group Ansaru on Saturday claimed to have killed all seven foreign hostages abducted from a construction site of Lebanese company Setraco on February 16 in the country's restive north.
According to the Greek foreign ministry, after assuming responsibility for the incident the kidnappers "at no stage carried out any communication or formulated any demands to release the hostages".
The group claimed that the hostages had been killed in retaliation for a rescue attempt by the British and Nigerian governments.
But the Greek foreign ministry denied this.
"Based on the information we have, there was no rescue operation," it said.
Police said the victims of the kidnapping in Bauchi state also included four Lebanese, one Briton and an Italian.
A company official later said the Middle Eastern hostages included two Lebanese and two Syrians.
Ansaru is considered a splinter faction of Islamist extremist group Boko Haram.