The recent cyberattack on a major IT provider to the NHS has been confirmed as a ransomware attack.

The IT provider Advanced, which supplies digital services to the NHS such as NHS 111, said it may take three to four weeks to fully recover. They did not say whether any NHS data had been stolen or whether the company was in negotiations with hackers or paying a ransom to them.

Advanced said: "We are rebuilding and restoring impacted systems in a separate and secure environment."

The NHS has said the disruption is minimal.

A spokesperson for NHS England said: "While Advanced has confirmed that the incident impacting their software is ransomware, the NHS has tried and tested contingency plans in place including robust defences to protect our own networks, as we work with the National Cyber Security Centre to fully understand the impact.

"The public should continue to use NHS services as normal, including NHS 111 for those who are unwell, although some people will face longer waits than usual.

"As ever, if it is an emergency, please call 999."

The National Cyber Security Centre, part of GCHQ, says it is working with Advanced to help it recover.

A spokesman said: "Ransomware is the key cyber-threat facing the UK, and all organisations should take immediate steps to limit risk by following our advice on how to put in place robust defences to protect their networks."