(Adds new attack, paragraphs 11-12) By Tume Ahemba and Tom Ashby LAGOS, Jan 25 (Reuters) - Gunmen abducted three Chinese workers at a Nigerian oilfield on Thursday, bringing to 32 the number of foreigners being held by armed groups in Africa's top oil producer. Seven other Chinese staff of the China National Petroleum Company (CNPC) were missing after the dawn raid in the southern state of Bayelsa, and one attacker was killed in an exchange of fire, authorities said. "There was an armed attack on a seismic team in Sagbama. Three Chinese were abducted and seven are unaccounted for," said Bisi Ojediran, a spokesman for Royal Dutch Shell <RDSa.L>. CNPC is working under contract to Shell in the area. "People ran helter skelter when the attackers arrived so maybe they are hiding somewhere. There is no report of casualties (among the Chinese) and a search is under way," Ojediran added. Police said the attackers also looted CNPC's field office and took away an unspecified amount of money. The Chinese embassy in Nigeria declined to comment. Militants and criminals seeking ransom have intensified attacks and kidnappings against foreign workers in the Niger Delta, a vast wetlands region which has all Nigeria's oil. Thousands of foreign oil workers have left in the past year as violence has spiralled, and some industry executives see the situation descending further into anarchy as landmark Nigerian elections approach in April. Nigeria is the world's eighth largest oil exporter, but militant raids last February have cut shipments by a fifth. In a separate incident on Thursday, two boatloads of heavily armed militants attacked an oilfield control station operated by Italy's Eni <ENI.MI> in neighbouring Rivers State, but were repelled by troops. There was no impact on output from the Obama oilfield. DRILLING RIGHTS Energy-hungry China has moved aggressively into Nigeria's oil heartland, despite the rising chaos. State-owned CNPC bought drilling rights to four oil licences in May in exchange for commitments to invest $4 billion in Nigerian infrastructure. China agreed to bid for an oil refinery in northern Nigeria and build a power station. Poverty and corruption fuel militancy and crime in the delta's neglected communities, where many feel cheated out of the oil wealth being pumped out of their land. In Rivers State on Tuesday, ransom seekers kidnapped an two engineers, one American and one Briton, at gunpoint from their car on the way to work. That followed the abduction of 24 Filipino seamen from a cargo ship in a remote creek in Delta State on Saturday. Those kidnappers are demanding the release of two jailed leaders from the delta, and a change in the ruling party's candidate for governor of the state in April's elections. The April elections should mark Nigeria's first fully democratic transition but many expect politicians to arm thugs to influence the polls, especially in the delta where elected office comes with a slice of oil revenue.
