The death toll has risen to at least 48 hostages killed during a four-day siege at a gas plant deep in the Sahara as a veteran Islamist fighter claimed responsibility on behalf of al Qaeda for the attack, Reuters reported.

Prime Minister Abdelmalek Sellal is expected to give details at a Monday, January 21 news conference about one of the worst international hostage crises in decades, which left American, British, French, Japanese, Norwegian and Romanian workers dead or missing.

A security source said on Sunday Algerian troops had found the bodies of 25 hostages, raising the number of militants and their captives killed to at least 80. He said six militants were captured alive and troops were still searching for others. One-eyed veteran Islamist fighter Mokhtar Belmokhtar claimed responsibility on Sunday for the attack on behalf of al Qaeda.

The fighters swooped out of the desert and seized the base on Wednesday, capturing a plant that produces 10 percent of Algeria's natural gas exports, as well as a nearby residential barracks. They demanded an end to French air strikes against Islamist fighters in neighboring Mali that had begun five days earlier.

The siege turned bloody on Thursday when the Algerian army opened fire saying fighters were trying to escape with their prisoners. Survivors said Algerian forces blasted several trucks in a convoy carrying both hostages and their captors.

Nearly 700 Algerian workers and more than 100 foreigners escaped, mainly on Thursday when the fighters were driven from the residential barracks. Some captors remained holed up in the industrial complex until Saturday when they were overrun.

The bloodshed has strained Algeria's relations with its Western allies, some of whom have complained about being left in the dark while the decision to storm the compound was being taken. Nevertheless, Britain and France both defended the Algerian military action.