A foreign worker taken hostage by gunmen in Nigeria's troubled oil-region has been released. The kidnapping was the first abduction of a foreign national for almost five months and raised fears that a period of relative calm in the Niger Delta could be coming to an end. For VOA, Sarah Simpson has more from Lagos.

The German construction worker has been released, unharmed, after about 12 hours in captivity. Gunmen took the man near the oil city, Port Harcourt, killing as many as three Nigerians, including soldiers, in the attack.

This is the first hostage-taking of a foreign national in the troubled region since October. However, hostage-taking of Nigerians - including children of families considered wealthy enough to pay a ransom - has remained a persistent problem.

Last year, more than 150 foreign nationals were abducted for ransom by criminal gangs operating in the oil-rich south.

Incidents fell after thousands of foreign workers and their families were evacuated from the oil-producing region. Security for those who remained was tightened.

New peace talks between the government of President Umaru Yar'Adua, inaugurated in May, and militant groups operating in the Delta has also contributed to the relative calm.

It is not clear whether this latest kidnapping was an isolated incident or the beginning of a new wave of attacks on foreigners.

The main militant group, the Movement for the Emancipation of the Niger Delta, has threatened a return to violence after one of its leaders was extradited to Nigeria by Angola, where he had been detained on gun-running charges.

MEND attacks on oil installations, including sabotage of pipelines and the kidnapping of foreigners, slashed Nigeria's crude production by about 20 percent and helped push global oil prices to record highs.

MEND says it is fighting so that a greater share of the national oil wealth is distributed to the Niger Delta.

But analysts say the violence has spiraled out of control and hostage-taking has become a lucrative criminal enterprise in a region awash with guns and mired in poverty.