(Adds president comment, context) By Tom Ashby LAGOS, Jan 18 (Reuters) - Six foreign hostages were freed in Nigeria's oil-producing delta on Thursday and President Olusegun Obasanjo voiced impatience with his policy of negotiation in the face of rising violence in Africa's oil heartland. Thousands of foreign oil workers have left Nigeria in the past year as attacks and kidnappings have multiplied, and some industry executives see the situation in the Niger Delta descending into anarchy as landmark elections approach in April. Beijing said five Chinese telecom workers kidnapped for ransom two weeks ago were "rescued", while the region's police chief said they were handed over by their captors to diplomats at a creek landing jetty in Rivers State capital Port Harcourt. An Italian, who had been ill, was released by a different group to a government official in neighbouring Bayelsa State. "The Chinese hostages were transferred peacefully to embassy officials at a waterfront in Port Harcourt," Rivers state Police Commissioner Felix Ogbaudu told Reuters by telephone. Ogbaudu said he did not have details of the deal that led to their release. The five Chinese were abducted by ransom-seekers who took them at gunpoint from their apartment on Jan. 5. Chinese state news agency Xinhua said they were "basically in good health". Italian hostage Roberto Dieghi, who suffered from a stomach illness during his near six-week ordeal, had been kept in the mosquito-infested swamps of the delta with three other staff from Italian oil company Eni <ENI.MI> since Dec. 7. Eni said Dieghi was in good condition and would be returned to Italy after medical tests. His colleagues, two Italians and one Lebanese, are being held by militants in southern Nigeria. NO EXCUSE Nigeria is the world's eighth-largest exporter. Militant raids last year have cut oil exports by a fifth. President Olusegun Obasanjo, opening an Abuja forum on the crisis in the delta on Thursday, said the crisis was costing the country dearly and said there was no excuse for kidnapping. "We have used carrot, we have used kid gloves and cannot continue indefinitely," he said. "It is not marginalisation making people take hostages ... it is simply criminality." April elections should mark Nigeria's first fully democratic transition and many expect politicians to arm thugs to gain sway at the polls, especially in the delta where elected office comes with a slice of oil revenue. Three people including one Dutch oil worker were killed on Tuesday when armed robbers dressed in army fatigues sprayed their boat with automatic fire near the Bonny Island oil and gas export complex, also in Rivers State. This followed the killing of 12 people including four community chiefs in an ambush on a ferry in the nearby Kula area on Sunday. Three oilfields were evacuated as a result. Poverty and neglect fuel crime and militancy in the Niger Delta, where many residents feel cheated out of the oil wealth pumped from their lands. In response to the growing anarchy in Rivers, Nigeria's top oil producing state, the navy will hold a major exercise in the waters off Bonny Island from Sunday to Friday next week. The operation will involve 14 ships, 6 smaller boats and four helicopter gunships, a military source said. "It will be on a massive scale. This is part of our new tactics to deal with these hooligans," said the source, asking not to be named. The Movement for the Emancipation of the Niger Delta (MEND), which is holding the remaining hostages, said it would keep the three men indefinitely and threatened to press its campaign of sabotage against the oil industry until its demands for autonomy were met. (Additional reporting by Estelle Shirbon in Abuja, Silvia Aloisi in Rome, Ben Blanchard and Vivi Lin in Beijing)
