A health board has asked patients not to attend hospital unless it is "essential" after its computer systems were hit by malware.
NHS Lanarkshire said it is carrying out further investigations into problems with its IT systems which began on Friday night.
The health board "took immediate action" to prevent the spread of the malicious software which can be triggered by anyone clicking on a malicious web link.
Calum Campbell, chief executive at NHS Lanarkshire, issued a statement on its Facebook page in response to the IT issues.
It 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."
The health board's estate includes Hairmyres Hospital in East Kilbride, Monklands Hospital in Airdrie and Wishaw General Hospital.
Staff were unable to use email systems or access appointments and instead directed the public to the HNS Lanarkshire Facebook site for further information
A later update on the site said: "We are still experiencing difficulties with our IT systems.
"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."