A military operation is continuing at an Algerian gas plant - three days after Al-Qaeda-linked fighters took hundreds of workers hostage.<br />More than 600 people are reported to have been released from the plant in the Sahara desert. But at least 30 people are still unaccounted for. <br />Algerian state media says 12 hostages and 18 gunmen have died in the operation.<br />Al Jazeera's Jamal Elshayyal reports.
