AP Moeller-Maersk AS (AMKBY)  said Wednesday that it has contained the Petya ransomware virus that shut down some of its systems in an ongoing global cyber attack but is still assessing its impact on the the world's biggest shipping company.

Maersk, one of the first companies to fall victim to the latest spread of ransomware, had temporarily shut down a shipping terminal in India, the country's biggest, following yesterday's attack but said key business units such as Maersk Oil and Maersk Drilling had not been "operationally affected".

"IT systems are down across multiple sites and select business units," the company said. "We have contained the issue and are working on a technical recovery plan with key IT-partners and global cyber security agencies."

The EU Agency for Law Enforcement Cooperation, known as Europol, said late Tuesday that it is working with companies and agencies around the region as the virus spreads from Europe to Asia in in what appears to be a coordinated series of attacks similar to the WannaCry crisis that spread around the world last month.

The attacks, according to multiple reports, have frozen IT systems and demanded a $300 cryptocurrency ransom to unlock trapped files.

WPP plc (WPPGY) shares extended declines Wednesday after the world's biggest advertising group said it was working to return to normal operations "as quickly as possible" following yesterday's incident.

WPP shares were marked 0.4% lower in London trading, after falling 0.8% yesterday, to change hands at 1,630.4 pence each.