Four Indian oil [Get Quote] workers were kidnapped in southern Sudan on Thursday, according to diplomatic sources.

Darfur rebels, who have been fighting a civilian war for five years in the region, denied any role in the abduction of the workers.

Deepak Vohra, Indian ambassador in Khartoum, confirmed the news. He said that every effort is being made to secure the release of the four Indians. 

According to diplomatic sources, the Indians were employees of an oil services company. They were kidnapped by disgruntled locals, who allege that the revenues from the oil-rich region don't reach them.

In October, the rebels had kidnapped five oil workers and warned the companies to immediately put an end to their work and leave Sudan. The hostages were eventually freed, after other countries intervened in the matter.

However, the rebels have vehemently denied any involvement in the kidnapping of the four Indians.