Five senior employees in a regional office of Algerian state energy firm Sonatrach have been arrested over corruption allegations, two sources close to Sonatrach told Reuters on Tuesday.

The arrests show that an official corruption investigation earlier this year which led to the suspension of Sonatrach CEO Mohamed Meziane and several top-ranking executives was still going on and was now extending to new areas.

The investigation into Meziane shocked many in Sonatrach, which supplies about 20 percent of Europe's natural gas, and also caused anxiety among foreign energy companies and energy service firms which work with Sonatrach.

Spokespeople for Sonatrach and Algeria's Energy Ministry did not respond to telephone calls requesting comment on the latest arrests, and a Justice Ministry official said she had no immediate comment.

The sources told Reuters the arrested employees included a senior manager at the company's regional downstream division in Oran, western Algeria, and four executives of a team based in the same office that awards contracts to suppliers.

A former finance director at the Oran division, who no longer works for Sonatrach, was also arrested, the sources said.

International attention will be focused on the city of Oran next month when it hosts a major liquefied natural gas conference and a meeting of the Gas Exporting Countries Forum, often referred to as "the gas OPEC."

After Meziane and other executives were placed under judicial investigation in January, senior Algerian officials said the investigation was part of a graft clean-up ordered by President Abdelaziz Bouteflika.

Some commentators though said the probe was linked to a power struggle between rival elements inside the ruling elite in Algeria, the world's eighth-biggest oil exporter and fourth largest exporter of gas.

Abdelwahab Djakoun, editor of pro-government newspaper La Nouvelle Republique, said the latest arrests showed Bouteflika was stamping down on graft in preparation for spending $150 billion over the next five years under a development plan.

"Clearing the way here means to fight corruption to make sure the money will develop the country and not create billionaires," Djakoun told Reuters.

Reuters