The Bulgarian government ordered an investigative news website and WikiLeaks partner to hand over the names of its sources and addresses of its reporters.

The letter the Bulgarian Financial Supervision Commission sent to the investigative outlet, Bivol.bg, on Dec. 8 said the organization wasn’t legally obliged to give the information but would face a fine of up to 4,000 euros if it didn’t, according to Reporters Without Borders, a France-based press freedom group.

Officials accused Bivol of “trafficking in confidential information” and “market manipulation,” following its publication of three articles about lending practices at Bulgaria’s Corporate Commercial Bank and First Investment Bank, or FiBank. The articles accused the two lenders of being drained of capital by loans to offshore shell companies and accused Bulgaria’s banking regulators of failing to adequately police them.

During the past year Bulgaria moved to open bankruptcy proceedings for Corporate Commercial Bank, the country’s fourth-largest lender. First Investment Bank, the country’s third-largest, was given liquidity assistance after a bank run by fearful depositors.

Bulgaria’s central bank also sent a letter to Bivol that said it would not investigate accusations made in the articles. It also warned the news site that “the dissemination of false information makes you liable under the law, especially when companies quoted on the stock exchanges are concerned.”

The exchange comes after weeks of similar exchanges between Bivol and Bulgaria’s banking industry, during which the investigative outlet published a series of articles criticizing the banking sector and accusing banking officials of corruption.