The University of Vermont Health Network, including six hospitals in Vermont and New York, on Friday was still dealing with a cyberattack that caused significant computer network problems, and an official said he did not know when the systems would be back online.

The network was working with the FBI and the Vermont Department of Public Safety on the investigation into the Wednesday attack and would not say if it was connected to other attacks hitting hospitals.

Adirondack Health, a neighboring network that serves the Tri-Lakes area, has not reported a cyberattack but is being cautious.

“Like hospitals and health systems across the country, Adirondack Health is closely monitoring this situation and working around the clock to protect our network infrastructure, while continuing to provide quality healthcare to those who depend on us,” Adirondack Health Chief Operating Officer Aaron Kramer said in a statement. “We have been in contact with peer facilities throughout northern New York, as well as state and federal law enforcement entities, to ensure all necessary lines of communication are maintained. All electronic communication sent to Adirondack Health is obviously subject to additional scrutiny at this time and responses will likely be delayed. For time-sensitive concerns, please contact us via telephone. Most departmental telephone numbers are available online at adirondackhealth.org.”

Communications Director Matt Scollin added that Adirondack Health has told nearby hospitals affected by the cyberattack that it has capacity to take some patients if needed.

The University of Vermont Medical Center did half of its normal scheduled surgeries on Friday, hospital President Dr. Stephen Leffler said Friday afternoon. It has about 380 patients in the hospital and has been providing “a full spectrum of care,” he said.

“We have been caring for people without issue,” Leffler said.

The FBI and two federal agencies warned in an alert Wednesday that they had “credible information of an increased and imminent cybercrime threat to U.S. hospitals and healthcare providers.” Independent security experts said Thursday that the ransomware, called Ryuk, has already affected at least five U.S. hospitals this week and could potentially affect hundreds more.

The UVM Health Network referred any questions about the investigation to the FBI, which would only confirm on Thursday that it was investigating “a potential cyberattack.”

“I know that our IT teams are making progress but we still have no set time when we believe that we’ll be able to bring our electronic medical record and other systems back online,” Leffler said. He expected it to be days, not weeks, before the system is working and said they had no reason to believe that medical information had been lost.

The hospital does not know when people who recently received COVID-19 tests will get the results, he said.

Republican Gov. Phil Scott said his administration was working with the hospital to ensure patient safety. “There has been no known impact to the state IT system,” he said.