Two Indian oil engineers have been captured by the Sudan People’s Liberation Army-In Opposition, rebel group that claims they were working with the country’s government. The news was confirmed by the group’s spokesperson William Gatjiath Deng on Friday. The engineers have been identified as Ambross Edward and Muggy Vijaya Boopathy who worked at an oilfield in Guelguk North along the Upper Nile.

Boopathy and Edward were captured during a fierce battle between government and rebel forces, the South Sudan Tribune reported. Deng said the Indians “refused to respect repeated warnings from the military command of the armed opposition”. Exiled Opposition leader Riek Machar will decide on what to do with them, Deng added, according to Hindustan Times. The group has been warning foreign oil workers from entering production sites in the country.

Neither the Indian Embassy in Juba not the Ministry of External Affairs has made a statement yet.

Oil production is a large contributor to South Sudan’s economy. The country has been ravaged by ethnic tension and civil war since 2013. It was culled out of Sudan in 2011 after 98.83% of its population voted for separation after a referendum.