Special measures imposed on NHS Greater Glasgow and Clyde by the Scottish government have been escalated amid ongoing concern over its performance.
The health board has faced criticism over its infection control procedures after the deaths of two children at the city's largest hospital complex.
It was partly placed in Stage 4 special measures in November.
Health Secretary Jeane Freeman has now extended these measures to cover the entire health board.
Ms Freeman and the health board both apologised in November to the parents of two young patients who died in 2017 in the Royal Hospital for Children, which is part of the Queen Elizabeth University Hospital (QEUH) campus.
A five-stage scale is used in Scotland to show the level of oversight for stricken health boards, with a stage four ranking given to a board where there are "significant risks to delivery, quality, financial performance or safety" with "senior level external support required".
Ms Freeman said the status will concentrate on scheduled care, unscheduled care, primary care out-of-hours, finance and culture and leadership.
She has previously announced specific support for infection prevention and control, communications and engagement after saying there were "ongoing issues" at the hospitals.
Calum Campbell, chief executive of NHS Lanarkshire, has been appointed as a "turnaround director" at NHSGGC to provide an "increased level of scrutiny and intervention", and will report to the Scottish government on the progress that has been made.
Ms Freeman said: "All of us, rightly, have high expectations of our NHS and I'm focused on improving performance and delivery across the system in order to provide the best care possible for the people of Scotland.
"In order to provide additional direction and support to NHS Greater Glasgow and Clyde I have taken the decision to escalate the board as a whole to stage 4 of the Performance Escalation Framework."
Three-year-old Mason Djemat, who was being treated for a rare genetic disease at the Royal Hospital for Children, died on 9 August 2017.
Milly Main, 10, died at the same hospital three weeks later while recovering from leukaemia treatment.
Both children were patients on a ward affected by water contamination, with their deaths emerging after Labour MSP Anas Sarwar was contacted by a whistleblower.
Mr Sarwar, who has previously exposed problems at the QEUH, said: "This is a step in the right direction, and it is encouraging that Jeane Freeman has recognised the scale of the crisis at NHS Greater Glasgow and Clyde.
"But the health board itself remains in complete denial of its catastrophic failings.
"It simply isn't tenable for those in charge to remain in post. They have lost the trust of patients, families and the public."
Meanwhile, the health secretary also announced additional steps to support NHS Highland and NHS Orkney.