SOFIA, Dec 2 (Reuters) - Kidnappers have freed a Bulgarian engineer who was abducted last month in Nigeria's oil-rich Niger Delta, the Bulgarian Foreign Ministry said on Tuesday.

Eight gunmen seized the man in the southeastern state of Abia two weeks ago, demanding 500 million naira ($3.77 million) for his release, a Nigerian private sector security source has said.

"The man was freed on November 30. He is in good health," said Dragovest Goranov, spokesman for the Bulgarian Foreign Ministry. He declined to comment on whether a ransom had been paid, although last week he said the sum being demanded was well below $4 million.

Kidnappings for ransom are frequent in the main oil-producing states of Delta, Rivers and Bayelsa in the Niger Delta, home to Nigeria's oil sector.

Security sources have said kidnappings are now on the rise in Abia state, although most have so far involved Nigerian captives. Abia is northeast of Rivers state. (Reporting by Anna Mudeva, editing by Mark Trevelyan)

AlertNet news is provided by