Hospital operations and GP appointments have been cancelled after a Scottish health board was hit by a cyber attack.

The hostile software was discovered on NHS Lanarkshire's computer network on Friday afternoon.

In May, NHS organisations around the UK were hit by a ransomware attack that sealed off files and demanded payment to unlock them.

While the nature of the latest cyber attack is not known, it has affected hospitals and GP practices and led to some operations and appointments being cancelled.

IT security experts have moved to prevent the spread of the attack and determine the scale of the problem.

No other Scottish health boards are affected.

NHS Lanarkshire chief executive Calum Campbell said malware had been discovered in the health board's computer network after IT issues were reported.

He said: "We have detected some incidences of malware. We took immediate action to prevent this spreading while we carried out further investigations.

"We are now putting in place a solution from our IT security provider.

"While the issue is being resolved our staff have been working hard to minimise the impact on patients and we apologise to anyone who has been affected."

Medical director for the acute division Dr Jane Burns is asking people to think before attending our emergency departments (EDs) while our systems are down.

She said: "I would ask that patients do not attend our hospitals unless it is essential. If you do turn up at A&E and do not require emergency care you may be sent away from the department or you may experience a lengthy wait.

"Emergency care will still be provided for those who do require to be seen."

NHS Lanarkshire serves a population of more than 650,000 people and is Scotland's third-largest health board.

The health board said its staff bank system was among the services affected by the issues.