STOCKHOLM (AFP) - Maersk, the Danish container and shipping giant crippled by a global cyberattack this week, said Thursday (June 29) most of its operations were now up and running again.

"We are able to accept bookings again," the company said on its website.

In addition, "the majority of our terminals are now operational. Some of these terminals are operating slower than usual or with limited functionality."

Maersk said on Wednesday that a number of its 76 container terminals were affected by the cyberattack and were forced to run on manual systems, but would not specify which sites.

"We continue to assess the situation. Until this analysis is complete, we cannot be specific about how many sites and locations are affected or when normal business operations are restored," Thursday's statement said.

Maersk's two terminals in Rotterdam, Europe's biggest port, were affected on Wednesday, as was a terminal run by Maersk at the Mumbai port, the largest in India.

When the systems are down, "we have to manage on a manual basis... It's difficult for people in the terminals to tell the people on the ground - the longshoremen - which containers to unload," Maersk chief operating officer Vincent Clerc said Wednesday.

Maersk's statement Thursday stressed that all of its vessels "continue to be under control, employees are safe and communication to crew and management onboard is functioning."

The series of cyberattacks began in Russia and Ukraine on Tuesday, hitting government and corporate computer systems across the world as the virus spread to western Europe and across the Atlantic.

Several other multinational companies said they were targeted, including US pharmaceutical giant Merck, Russian state oil giant Rosneft, British advertising giant WPP and the French industrial group Saint-Gobain.