LONDON (Reuters) - BP said on Saturday that 14 of its 18 employees at the In Amenas plant in Algeria were safe but the fate of the remaining four remained unknown as the hostage crisis there was drawing to a close.
"While not confirmed, tragically we have grave fears that we are likely to have suffered one or more casualties," said Bob Dudley, chief executive of the oil and gas giant, during a conference call with reporters.
"This was an unprovoked, violent assault by heavily armed murderers," he said.
The Algerian army carried out a dramatic final assault earlier on Saturday to end a siege of the desert plant by Islamic militants who attacked it on Wednesday. Details of casualties were still hazy.
Dudley declined to disclose the nationalities of the four employees still missing or of the 14 who were safe, but when a reporter brought up the name of American Mark Cobb, manager of the In Amenas joint venture, Dudley confirmed that Cobb was safe.
Two of the 14 employees who are safe sustained injuries but these were not life-threatening and the pair had already been flown out of Algeria, Dudley said.
"The information I've had from the Algerian energy ministry is that the active operation has been completed, that the terrorists had an intention of potentially destroying the entire facility and there are explosives and mines involved and it is being very systematically being walked through by the Algerian military," Dudley said.
Dudley said that typically there were 500 to 700 people on site at the In Amenas plant, most of whom were Algerian. The minority of foreigners who worked there included citizens from more than 25 countries.
He said BP usually had around 20 people at In Amenas and 60 in the whole of Algeria.
The firm was in the process of evacuating non-essential staff from Algeria as a precautionary measure, he said, and 25 had already left.
Dudley said BP's intention was to return to normal operations in Algeria as soon as circumstances allowed.
He also said that BP was reviewing security at other installations in the region, but did not give any details.
Asked for details about how and when operations at In Amenas had been shut down, Dudley said that within three or four hours of the start of the attack on Wednesday BP had received a report that the gas wells had been isolated from the facility.
This meant the flow of gas to the facility was closed first, and then the vessels and processing equipment were vented down so there was no longer high-pressure in the plant, he said.
"What that meant is that there were a number of vessels that remained with liquid hydrocarbons in them throughout this event," Dudley said.