Russian e-commerce giant Wildberries said a cyberattack has delayed payments to some sellers, leaving merchants on the hook for billions of unpaid rubles until a solution is found.

Wildberries told several Russian media outlets earlier this week that payments to some sellers were delayed by security measures introduced after a distributed denial-of-service (DDoS) attack targeted systems used to track and withdraw their earnings.

The company said sellers’ funds remained safe and would be transferred once the necessary “technical procedures” were completed.

Wildberries did not disclose details of the attacks or attribute them to a specific group. Earlier in August, however, Ukraine’s military intelligence said it had disrupted the company’s operations in a cyberattack carried out alongside a hacker group known as Cyber Corps.

Earlier this month, sellers complained that payments for goods sold through the marketplace had been delayed for weeks. The Russian Union of Marketplace Sellers said about 20 billion rubles ($240 million) remained unpaid for goods sold during the final week of July. A survey by the group of nearly 2,000 sellers found that 95.6% had not received payments they were expecting.

In a letter to Russian Prime Minister Mikhail Mishustin, the association asked the government to take the issue under its supervision and called on Russia’s antitrust authority to examine the delays. It also asked the tax service to account for the cash-flow problems facing businesses that have not received their money.

Wildberries told Russian newspaper Kommersant that most sellers had received their money but acknowledged that some payments remained delayed because of the DDoS attack.

The company said its security systems can temporarily suspend the processing of some transfers during an attack, meaning withdrawal requests can take longer than usual.

The sellers’ union questioned that explanation, saying it was “very convenient to hide behind external factors, especially technical ones.” It also claimed that foreign sellers continued to receive payments on schedule during the same period.

Ukrainian attack

Ukraine’s Main Intelligence Directorate, known as HUR, said last month that an operation conducted with the Cyber Corps hacking group caused widespread disruption to Wildberries’ digital infrastructure, affecting customer service, contact centers and payment systems.

The intelligence agency said the operation was intended to amplify the damage from Ukrainian strikes on Wildberries warehouses. Wildberries did not publicly confirm the Ukrainian intelligence agency’s claims or say whether the DDoS attacks blamed for the payment delays were connected to that operation.

Wildberries maintains a vast logistics network and is one of Russia’s largest online marketplaces, which is often compared to Amazon.

Russian media have estimated that the company has lost more than 1.2 million square meters of warehouse space in Ukrainian attacks.

While most goods sold through the platform are ordinary consumer products, Wildberries has also reportedly offered military-related equipment, including drone components and body armor.