Oil thieves opened fire on a boat carrying workers for the state oil firm in Nigeria over the weekend, killing three engineers, the company said on Monday. The engineers had been dispatched to try to repair damage to a pipeline carrying petroleum products that the thieves had hacked near Lagos in the southwest, a statement from the Nigeria National Petroleum Corporation (NNPC) said. The engineering crew managed to switch off petrol going to the punctured pipeline but when they tried to get access to the site to assess the damage, they were fired upon, it added. "Nigerians need to identify with the NNPC and recognize that it is our collective responsibility to work towards securing the nation's oil installations," spokesman Fidel Pepple was quoted as saying by Reuters.