* Thirty hostages, at least seven foreign, killed - source
* More than 20 foreigners still held or missing on Friday
* Western governments not consulted, Algiers faces questions
* 10 Japanese, 8 Norwegians, "less than 30" Britons at risk
By Lamine Chikhi and Abdelaziz Boumzar
ALGIERS/IN AMENAS, Algeria, Jan 18 (Reuters) - More than 20foreigners were still either being held hostage or missinginside a gas plant on Friday after Algerian forces stormed thedesert complex to free hundreds of captives taken by Islamistmilitants.
More than a day after the Algerian army launched an assaultto seize the remote desert compound, much was still unclearabout the number and fate of the victims, leaving countries withcitizens in harm's way struggling to find hard information.
Reports on the number of hostages killed ranged from 12 to30, with anywhere from dozens to scores of foreigners stillunaccounted for.
Norway's Prime Minister Jens Stoltenberg, eight of whosecountrymen were missing, said fighters still controlled the gastreatment plant itself, while Algerian forces now held thenearby residential compound that housed hundred of workers.
Leaders of Britain, Japan and other countries expressedfrustration that the assault had been ordered withoutconsultation. Many countries were also withholding informationabout their citizens to avoid helping the captors.
Night fell quietly on the village of In Amenas, the nearestsettlement, some 50 km (30 miles) from the vast and remotedesert plant. A military helicopter could be seen in the sky.
An Algerian security source said 30 hostages, including atleast seven Westerners, had been killed during Thursday'sassault, along with at least 18 of their captors. Eight of thedead hostages were Algerian, with the nationalities of the restof the dead still unclear, he said.
Algeria's state news agency APS put the total number of deadhostages at 12, including both foreigners and locals.
Norway's Stoltenberg said some of those killed in vehiclesblasted by the army could not be identified. "We must beprepared for bad news this weekend but we still have hope."
Northern Irish engineer Stephen McFaul, who survived, saidhe saw four trucks full of hostages blown up by Algerian troops.
The attack has plunged international capitals into crisismode and is a serious escalation of unrest in northwesternAfrica, where French forces have been in Mali since last weekfighting an Islamist takeover of Timbuktu and other towns.
"We are still dealing with a fluid and dangerous situationwhere a part of the terrorist threat has been eliminated in onepart of the site, but there still remains a threat in anotherpart," British Prime Minister David Cameron told his parliament.
A local Algerian source said 100 of 132 foreign hostages hadbeen freed from the facility. However, other estimates of thenumber of unaccounted-for foreigners were higher. Earlier thesame source said 60 were still missing. Some may be heldhostage; others may still be hiding in the sprawling compound.
Two Japanese, two Britons and a French national were amongthe seven foreigners confirmed dead in the army's storming, theAlgerian security source told Reuters. One British citizen waskilled when the gunmen seized the hostages on Wednesday.
Those still unaccounted for on Friday included 10 from Japanand eight Norwegians, according to their employers, and a numberof Britons which Cameron put at "significantly" less than 30
France said it had no information on two Frenchmen who mayhave been at the site and Washington has said a number ofAmericans were among the hostages, without giving details. Thelocal source said a U.S. aircraft landed nearby on Friday.
The attackers had initially claimed to be holding 41 Westernhostages. Some Westerners were able to evade capture by hiding.
They lived among hundreds of Algerian employees on thecompound. The state news agency said the army had rescued 650hostages in total, 573 of whom were Algerians.
"(The army) is still trying to achieve a 'peaceful outcome'before neutralising the terrorist group that is holed up in the(facility) and freeing a group of hostages that is still beingheld," it said, quoting a security source.
MULTINATIONAL INSURGENCY
Algerian commanders said they moved in on Thursday about 30hours after the siege began, because the gunmen had demanded tobe allowed to take their captives abroad.
A French hostage employed by a French catering company saidhe had hidden in his room for 40 hours under the bed, relying onAlgerian employees to smuggle him food with a password.
"I put boards up pretty much all round," Alexandre Berceauxtold Europe 1 radio. "I didn't know how long I was going to staythere ... I was afraid. I could see myself already ending up ina pine box."
The captors said their attack was a response to a Frenchmilitary offensive in neighbouring Mali. However, some U.S. andEuropean officials say the elaborate raid probably required toomuch planning to have been organised from scratch in the singleweek since France first launched its strikes.
Paris says the incident proves that its decision to fightIslamists in neighbouring Mali was necessary.
Security in the half-dozen countries around the Saharadesert has long been a pre-occupation of the West. Smugglers andmilitants have earned millions in ransom from kidnappings.
The most powerful Islamist groups in the Sahara wereseverely weakened by Algeria's secularist military in a civilwar in the 1990s. But in the past two years the regional wing ofAl Qaeda gained fighters and arms as a result of the civil warin Libya, when arsenals were looted from Muammar Gaddafi's army.
Al Qaeda-linked fighters, many with roots in Algeria andLibya, took control of northern Mali last year, prompting theFrench intervention in that poor African former colony.
The Algerian security source said only two of 11 militantswhose bodies were found on Thursday were Algerian, including thesquad's leader. The others comprised three Egyptians, twoTunisians, two Libyans, a Malian and a Frenchman, he said.
The plant was heavily fortified, with security, controlledaccess and an army camp with hundreds of armed personnel betweenthe accommodation and processing plant, Andy Coward Honeywell,who worked there in 2009, told the BBC.
The apparent ease with which the fighters swooped in fromthe dunes to take control of an important energy facility, whichproduces some 10 percent of the natural gas on which Algeriadepends for its export income, has raised questions over thevalue of outwardly tough security measures.
Algerian officials said the attackers may have had insidehelp from among the hundreds of Algerians employed at the site. The attackers benefitted from bases and staging grounds acrossthe nearby border in Libya's desert, Algerian officials said.
U.S. Defense Secretary Leon Panetta said those respsonsiblewould be hunted down: "Terrorists should be on notice that theywill find no sanctuary, no refuge, not in Algeria, not in NorthAfrica, not anywhere.... Those who would wantonly attack ourcountry and our people will have no place to hide."
WARNING OF MORE ATTACKS
The kidnappers threatened more attacks and warned Algeriansto stay away from foreign companies' installations, according toMauritania's news agency ANI, which maintained contact with thegroup during the siege.
Hundreds of workers from international oil companies wereevacuated from Algeria on Thursday and many more will follow,said BP, which jointly ran the gas plant with Norway's Statoiland the Algerian state oil firm.
The overall commander of the kidnappers, Algerian officialssaid, was Mokhtar Belmokhtar, a one-eyed veteran of Afghanistanin the 1980s and Algeria's bloody civil war of the 1990s. Heappears not to have been present.
Algerian security specialist Anis Rahmani, author of severalbooks on terrorism and editor of Ennahar daily, told Reutersabout 70 militants were involved from two groups, Belmokhtar's"Those who sign in blood", who travelled from Libya, and thelesser known "Movement of the Islamic Youth in the South".
Britain's Cameron, who warned people to prepare for bad newsand who cancelled a major policy speech on Friday to deal withthe situation, said he would have liked Algeria to haveconsulted before the raid. Japan made similar complaints.
U.S. officials had no clear information on the fate ofAmericans. Washington, like its European allies, has endorsedFrance's military intervention in Mali.