In an exclusive interview with Al Jazeera, Meles Zenawi, the Ethiopian prime minister, said that Ethiopia knows "who was involved, and knows that the Eritrean intelligence section led the kidnapping of the individuals, and knows that the hostages were taken across the border, and therefore hold Eritrea fully responsible".
Eritrean authorities are yet to comment.
Zenawi called on the "international community" to bring more sanctions against the country.
The three British men and two women – one with dual British-Italian nationality and one French national – left the Eritrean capital at around 3:30pm (12:30 GMT), the source said.
Some of them traveled to London and others were returned to their homes in Addis Ababa, the source added.
British authorities also expressed concern Wednesday for the eight missing Ethiopians captured with the embassy group in the remote Ethiopian desert on March 1.
On Tuesday, Margaret Beckett told reporters that the five European hostages were released to the Eritrean authorities and into in the care of the British embassy in Asmara.
The three British men, one Italian-British woman and a French woman all have links to the British diplomatic community in the Ethiopian capital of Addis Ababa.
|Margaret Beckett, the British foreign minister, |
said the hostages were in good health [AP]
Regional officials and Afar locals had said the hostages were marched into neighbouring Eritrea - something Eritrea had earlier denied.
Beckett said there were varying reports as to where the hostages had been held but "certainly they were released with the help of the Eritrean government".
The five Europeans were named as Peter Rudge and Jonathan Ireland, first secretary and administrative support at the British embassy in Addis Ababa, Malcolm Smart and Laure Beaufils working for the Department for International Development in the Ethiopian capital and Rosanna Moore, wife of the head of the British Council there.