Suspected armed militants attacked a Chinese oil company in the Southern Nigeria state, Bayelsa, Thursday, kidnapping at least two Chinese workers. From Abuja, Gilbert da Costa reports the latest hostage-taking is adding to growing concerns about violence in the region.

Bayelsa State Police Commissioner Hafiz Ringim confirmed the attack. He says one of the assailants died, following a shoot-out with security forces.

He told VOA the gunmen also broke into the finance offices of the China Petroleum Company and stole some money.

"There was an attack in the morning, about two, three people kidnapped," he said. "It happened six in the morning, barely four, five hours ago. They [attackers] burgled the accounts office, but one militant was killed."

Some 100 hostages - mainly workers in the oil industry - have been kidnapped in the Niger Delta, in the past year.

Thursday's abduction was the second involving Chinese this month in the restive oil-rich region.

Five Chinese telecom workers seized by unidentified gunmen on January 5 were released last week.

Separatist groups fighting for a greater share of Nigeria's oil wealth have stepped up their campaign to cripple the multi-billion-dollar industry.

Hostages are often released after a few days or weeks in captivity, with the payment of ransom. A group of 24 Filipinos, abducted last week, is still being held.

Persistent violence in the Niger Delta has hampered oil production in the region, cutting output by a quarter.