(Reuters) - A federal judge in Manhattan has ruled that a group of Sudanese refugees can move ahead with a proposed class action seeking to hold French bank BNP Paribas accountable for financing the government regime that committed genocide in the country.

U.S. District Judge Alison Nathan found on Tuesday that the refugees had plausibly alleged a claim under Swiss law that BNP Paribas was an accomplice to the torture, rape and murder of Sudanese citizens as the regime's main bank from 1997 to 2007.

Kathryn "Lee" Boyd of Hecht Partners and Brent Landau of Hausfeld, who represent the refugees, said in a statement on Tuesday the ruling confirms that entities can be held civilly liable for "willful or negligent complicity in human rights abuses."

"Thousands of Sudanese refugees — who have never received any compensation — are one step closer to justice today," they said.

BNP Paribas spokesman Guy Taylor declined to comment. Carmine Boccuzzi of Cleary Gottlieb Steen & Hamilton represented the bank.

In a 2016 lawsuit, 21 Sudanese refugees living in the U.S. alleged BNP Paribas' banking relationship with the regime of former president Omar al-Bashir allowed it to evade sanctions and access the U.S. financial system. That enabled the regime to sell the country's oil and buy weapons used against the Sudanese people, they claimed.

Nathan had ruled in March that Swiss law governs the case because BNP Paribas' Geneva branch handled correspondent banking for Sudanese banks.

The bank has raised several defenses, including that it was too far removed from the violence to for the refugees to state a claim under Swiss law.

A claim for secondary liability under Swiss law must include allegations that the defendant "knew or should have known" they were contributing to an illicit act, and that their actions were the "natural and adequate cause" of the harm. The bank and refugees disagreed as to what those standards required.

On Tuesday, Nathan said she found the plaintiffs' expert, Franz Werro, a law professor whose works have been cited by the Swiss Supreme Court, convincing. Based on his interpretation, Nathan found that a claim the bank was negligent was enough to satisfy the knowledge element. And the refugees had a valid claim the bank was a "natural cause" of the harm because they alleged that its actions contributed to the scope of the atrocities, she wrote.

Interpreting the "adequate cause" requirement, the judge said the standard is whether it would be reasonable to hold BNP Paribas liable for the atrocities, based in part on whether they were foreseeable to the bank at the time.

While acknowledging that there were several links in the chain between the bank and the refugees' injuries, the judge wrote that they had alleged BNP Paribas profited from more business after the regime grabbed oil-rich lands.

"It is more reasonable to consider BNPP the adequate cause of the violence when the violence was allegedly perpetrated to increase and continue that profitable business relationship," she wrote.

BNP Paribas pleaded guilty in June 2014 and agreed to pay an $8.97 billion penalty to settle U.S. charges it transferred billions of dollars for Sudanese, Iranian and Cuban entities subject to economic sanctions.

Bashir, who seized power in a bloodless coup in 1989, was overthrown by the country's military in 2019. He faces charges in Sudan and is wanted by the International Criminal Court on charges of genocide, war crimes and crimes against humanity in Sudan's Darfur region.

The case is Kashef et al. v. BNP Paribas SA et al., No. 16-cv-03228, in U.S. District Court for the Southern District of New York.

For the proposed class: Kathryn "Lee" Boyd of Hecht Partners and Brent Landau of Hausfeld

For the bank: Carmine Boccuzzi of Cleary Gottlieb Steen & Hamilton