The Port of Nagoya began gradually resuming operations Thursday afternoon, the Nagoya Harbor Transportation Association said, after an alleged Russian ransomware attack disrupted cargo packing procedures earlier this week.

Operations at one cargo terminal resumed Thursday at 3 p.m., the association said in a statement. It aims to restart another terminal by 5:30 p.m., and three others by 6:30 pm.

Systems at Japan’s biggest maritime port were restored earlier, but operations took longer to recover, according to the association. The facility was scheduled to resume activity earlier in the day but the recovery of large amounts of deleted data had delayed the process.

The ransomware attack, in which hackers block access to files or systems and demand a payment in return for access, caused the container terminal at the port in Aichi Prefecture to halt operations Tuesday morning, the Nagoya Harbor Transportation Authority said Wednesday.

“As cybersecurity risks become more complex, the country’s security systems and countermeasures to such threats are increasingly important,” Chief Cabinet Secretary Hirokazu Matsuno said Thursday, when asked about the attack.

Toyota Motor Corp., the world’s biggest carmaker by units sold, said the attack in Nagoya on Tuesday won’t affect the shipment of new cars yet, but imported and exported parts cannot be loaded or unloaded at the port until the problem is resolved. There wasn’t any impact on production as of Thursday morning, according to a spokesperson for the carmaker.

Nagoya is one of several ports globally to be recently targeted by malware. Last Christmas, hackers broke into the computer systems at Portugal’s Port of Lisbon, holding up operations for days. Jawaharlal Nehru Port Trust, India’s busiest container port, also suffered a ransomware attack last year. In 2021, South Africa’s port and rail company was targeted with a strain of ransomware that cybersecurity experts have linked to groups in Eastern Europe and Russia.

Authorities in Japan say such attacks are on the rise. Last year, a cyberattack on one of Toyota’s suppliers in Aichi Prefecture forced it to halt operations at 14 factories.