NHS Wales 'not impacted by cyber attack' after England hit
NHS Wales has said none of its computer systems have been impacted and no patient data affected by a global cyber-attack.
Suspicious activity was identified on six computers on part of its network.
"Our systems prevented the virus activating and the machines were isolated," a Welsh Government spokesman said.
But email blocks have been extended for another 24 hours within the Welsh health service as a precaution.
The Welsh Government said precautionary measures had been taken "to ensure the integrity of the system and we continue to monitor the situation closely".
"We have recently invested in upgrading IT to protect potentially vulnerable NHS Wales systems and all GP systems in Wales are managed and supported centrally, with best practice security controls.
"Additional steps continue to be taken to protect NHS IT systems and we would like to thank National Wales Informatics Service (NWIS) and IT teams across the NHS who have been working tirelessly over the weekend."
As a precaution, the NHS in Wales announced over the weekend that all external emails sent into the organisation (including from NHS England) had been blocked and would be deleted automatically.
There are also restrictions on staff use of external email accounts, for example Gmail and Hotmail.
Staff, however, can still receive internal emails from colleagues within Wales and send out-going emails.
IT experts in the NHS across Wales have been working "flat out" over the weekend to protect health-board IT systems.
Dr Fiona Jenkins, executive director in charge of IT at Cardiff and Vale University Health Board, said it had been largely unaffected and there had been no impact on any patient services or data.
"We are indebted to our IT staff who have worked day and night throughout the weekend to ensure that all our systems have the best possible protection against these senseless attacks," she said.
There has been a lockdown with emails deleted from external sources and staff advised to reboot all computers, while flagging up anything out of the ordinary.
"However, we are not complacent and will be continuing to ensure that we continue to have the best IT security and to properly secure data and information," said Dr Jenkins.
Steve Moore, chief executive of Hywel Dda University Health Board, said staff had been working to strengthen IT security all weekend.
"Whilst we've not been infected we are taking extra precautions to keep our patients safe, one of which is to keep our email systems shut down until we are confident there is no further risk," he said.
"We are asking people who may need to contact our services to do so by phone and to please bear with us as our lines will be busier than usual. We apologise for the inconvenience and hope that everyone understands why we are taking these measures."