LONDON — A South Sudanese oil consortium directly financed militias accused of committing atrocities in the country’s civil war, according to an investigative report released on Thursday amid growing calls for accountability for the conflict’s human rights abuses.

The report by a watchdog group linked the consortium, Dar Petroleum Operating Company, in which Chinese- and Malaysian state-owned oil companies have large stakes, to episodes of violence, corruption and environmental degradation. It also outlined ties between forces loyal to the government of President Salva Kiir and the company, a relationship apparently forged in an effort to protect the oil fields and keep revenues flowing.

South Sudan’s oil fields, the primary source of the government’s wealth, have long been one of the pathways to finance the civil war. But the detailed report by the watchdog group the Sentry, released at a news conference in London on Thursday, attempts to further shore up the evidence of the international players believed to be complicit in the civil war, which has lasted six years, almost as long as the country has existed. The Sentry was founded by the actor George Clooney and John Prendergast, a rights activist.

While experts say there are few accountability mechanisms in place in South Sudan, the naming and shaming of major international organizations and individuals could prove financially damaging. The authors also hope the report would spur action from banks and governments, such as seizing assets and imposing sanctions on those named.