UPDATE 5-Nigerian militants free one of two British hostages

* Militants release British hostage Hughes

* One Briton still being held by militant group

* Hundreds of foreigners kidnapped in recent years (Updates with militant group comments, details)

By Randy Fabi

ABUJA, April 19 (Reuters) - Nigeria's most prominent militant group on Sunday released one of two British hostages that were kidnapped in the restive Niger Delta seven months ago.

Hundreds of foreigners have been seized in the Delta, home to Africa's biggest oil and gas industry, since MEND launched a campaign of violence in early 2006 to push for what it considers to be a fairer share of the profits from crude oil extraction. Most have been freed unharmed after a few weeks.

MEND, responsible for attacks that have cut Nigeria's oil production by one fifth in recent years, had said it would release the Briton because of his health and age. It added that no ransom was paid.

"The Movement for the Emancipation of the Niger Delta (MEND) can confirm that the British hostage Mr Robin Barry Hughes regained his freedom about 1730 hours (1630 GMT) today," a spokesman for the group said in an emailed statement.

Military and diplomatic officials also confirmed his release in Port Harcourt, capital of Rivers state in southeastern Nigeria.