DLA Piper has been hit by a major cyber attack, which has knocked out phones and computers across the firm.

The shutdown appears to have been caused by a ransomware attack, similar to the WannaCry attack that hit organisations such as the UK's National Health Service (NHS) last month.

DLA's phone system has not been working for much of the day and partners say they have been instructed to turn off their computers as a precaution.

Offices in the UK, Europe, the Middle East and the US called by Legal Week all seem to have been affected, with some inside the firm saying email and phone systems have been affected and other systems then locked down as a precaution.

One partner in the firm's London office said: "I'm aware the firm's IT guys have shut the systems down as a precautionary measure in response. It's very frustrating – I'll have a lot of emails to deal with later. I can't believe there's been another global attack so soon after the last one."

DLA said in a statement: "The firm, like many other reported companies, has experienced issues with some of its systems due to suspected malware. We are taking steps to remedy the issue as quickly as possible."

The BBC is reporting that multiple organisations have been affected by the hack, including Russian oil producer Rosneft and Danish shipping company Maersk.

The news comes after the WannaCry ransomware attack hit organisations around the world in May, including the UK's NHS.

Steve Hill, ex-deputy director in the UK government National Security Secretariat dealing with cyber security told Legal Week at that time: "There is a huge criminal cyber threat to law firms. The hackers perpetrating these types of attacks will not be teenage boys – they are criminal gangs set up to exploit law firms for sensitive data or lock people out of the data in return for a ransom."

Fieldfisher managing partner Michael Chissick commented: "This has been a global hack, with numerous businesses and firms reporting problems. This is the reality of the modern world and hackers will keep trying to attack business in all forms. All law firms, including DLA, are doing their utmost to protect clients and themselves."