Algeria's four-day hostage stand-off came to a bloody end today when the country's special forces stormed the remote desert gas plant and killed 11 militants, but not before they in turn executed seven hostages, the state news agency reported.

The report, quoting a security source, did not specify if any hostages or militants remained alive or give the nationalities of the dead.

Algerian authorities estimated that around 30 militants occupied the In Amenas facility on Wednesday and, with 18 already reported dead, it appears the hostage crisis involving hundreds of plant workers is finally over.

There was no official count of how many hostages were still being held by the final group of militants holed up in the gas refinery today, but the militants themselves had reported they were still holding three Belgians, two Americans, a Japanese and a Briton.

The plant is jointly run by BP, Norway's Statoil and Algeria's state-owned oil company.

An international outcry mounted over the Algerians' handling of the crisis. Experts noted that this is how they have always dealt with terrorists, refusing to negotiate.

The siege has put the spotlight on militancy plaguing the region and al Qaida-linked groups roaming remote areas from Mali to Libya, threatening vital infrastructure and energy interests.