A veteran Islamist fighter claimed responsibility on behalf of al Qaeda for the Algerian hostage crisis, a regional website reported on Sunday, tying the bloody desert siege to France's intervention across the Sahara in Mali.
Algeria said it expected to raise its preliminary death tolls of 23 hostages and 32 militants killed in the four-day siege at a gas plant deep in the Sahara.
Western governments whose citizens died nevertheless held back from criticizing tactics used by their ally in the struggle with Islamists across the vast desert.
"We in al Qaeda announce this blessed operation," Mokhtar Belmokhtar said in a video, according to the Sahara Media website, which quoted from the recording but did not immediately show it.
"We are ready to negotiate with the West and the Algerian government provided they stop their bombing of Mali's Muslims," said Belmokhtar, a one-eyed veteran guerrilla who fought in Afghanistan in 1980s and in Algeria's civil war in the 1990s.
Belmokhtar's fighters launched their attack on the In Amenas gas plant before dawn on Wednesday, just five days after French warplanes began strikes to halt advances by Islamists in neighboring northern Mali.
European and U.S. officials say the raid was almost certainly too elaborate to have been planned in so short a time, although the French campaign could have been one trigger for fighters to launch an assault they had already prepared.
"We had around 40 jihadists, most of them from Muslim countries and some even from the West," Sahara Media quoted Belmokhtar as saying. Algerian officials say Belmokhtar's group was behind the attack but he was not present himself.
Some Western governments have expressed frustration at not being informed in advance of the Algerian authorities' plans to storm the complex. However, Britain and France both defended the Algerian action in public.
"It's easy to say that this or that should have been done. The Algerian authorities took a decision and the toll is very high but I am a bit bothered ... when the impression is given that the Algerians are open to question. They had to deal with terrorists," French Foreign Minister Laurent Fabius said.
British Prime Minister David Cameron said in a televised statement: "Of course people will ask questions about the Algerian response to these events, but I would just say that the responsibility for these deaths lies squarely with the terrorists who launched this vicious and cowardly attack."
"We should recognize all that the Algerians have done to work with us and to help and coordinate with us. I'd like to thank them for that. We should also recognize that the Algerians too have seen lives lost among their soldiers."
OIL VULNERABILITIES EXPOSED
The Islamists' assault has tested Algeria's relations with the outside world, exposed the vulnerability of multinational oil operations in the Sahara and pushed Islamist radicalism in northern Africa to centre stage.
Algeria, scarred by the civil war with Islamist insurgents in the 1990s which claimed 200,000 lives, has insisted there would be no negotiation in the face of terrorism.
France especially needs close cooperation from Algeria to have a chance of crushing Islamist rebels in northern Mali. Algiers has promised to shut its porous 1,000-km border with Mali to prevent al Qaeda-linked insurgents simply melting away into its empty desert expanses and rugged mountains.
Algeria's permission for France to use its airspace, confirmed by Fabius last week, also makes it much easier to establish direct supply lines for its troops which are trying to stop the Islamist rebels from taking the whole of Mali.
Algeria's Interior Ministry had reported on Saturday that 23 hostages and 32 militants were killed during the assaults launched by Algerian special forces to end the crisis, with 107 foreign hostages and 685 Algerian hostages freed.
Minister of Communication Mohamed Said said the toll would rise when final numbers were issued in the next few hours: "I am afraid unfortunately to say that the death toll will go up," Said was quoted as saying by the official APS news agency.
Private Algerian television station Ennahar said on Sunday that 25 bodies had been discovered at the Tiguentourine plant, adding that the operation to clear the base would last 48 hours.
The bodies were believed to belong to hostages executed by the militants, said Ennahar TV, which is known to have good sources within Algerian security.
With so much still unknown about the fates of foreigners held at the sites, countries that have faced casualties have yet to issue full counts of the dead. The plant was run jointly by Britain's BP and Norway's Statoil with the Algerian state oil company. A Japanese engineering firm and a French catering company also operated there.
In London, Cameron said three British nationals were confirmed killed and another three plus a British resident were also believed to be dead. One American has been confirmed killed. Statoil says five Norwegians are missing. Japanese and French citizens are also among those missing or presumed dead.
Said reported that the militants had six different nationalities and the operation to clear the plant of mines laid by the hostage-takers was still under way.
Believed to be among the 32 dead militants was their leader, Abdul Rahman al-Nigeri, a Nigerien close to Belmokhtar.
Mauritanian news agencies identified the field commander of the group that attacked the plant as Nigeri, a fighter from one of the Arab tribes in Niger who had joined the Algerian Salafist Group for Preaching and Combat (GSPC) in early-2005.
That group eventually joined up with al Qaeda to become Al Qaeda in the Islamic Maghreb (AQIM). It and allied groups are the targets of the French military operation in Mali.
The apparent ease with which the fighters swooped in from the dunes to take control of an important energy facility, which produces some 10 percent of the natural gas on which Algeria depends for its export income, has raised questions over the country's outwardly tough security measures.
Algerian officials said the attackers may have had inside help from among the hundreds of Algerians employed at the site.
Security in the half-dozen countries around the Sahara desert has long been a preoccupation of the West. Smugglers and militants have earned millions in ransom from kidnappings.
The most powerful Islamist groups operating in the Sahara were severely weakened by Algeria's secularist military in the civil war in the 1990s. But in the past two years the regional wing of al Qaeda gained fighters and arms as a result of the civil war in Libya, when arsenals were looted from Muammar Gaddafi's army.