Sanford Health and Fairview Health Services are again delaying their proposed merger, announcing Monday a new timeline that prevents a closing before late August.

The health systems also said Monday they would provide a 90-day notice of the closing, per a request from Minnesota Attorney General Keith Ellison's office.

"We remain confident in the benefits of the merger," the health systems said in a statement.

Ellison's office said the attorney general did not make a specific request for the latest extension but learned of it from the health systems Friday. The attorney general has said repeatedly the schedule the health systems proposed created unnecessary time pressures for his investigation.

"In order to prevent a future surprise announcement of a new closing date by the parties that might impact the office's investigation, the [attorney general's office] requested that any future proposed closing date be provided with a minimum of 90 days' notice to us, to which the parties agreed," Ellison's office said in a statement.

In February, South Dakota-based Sanford and Minneapolis-based Fairview agreed with Ellison's office to delay their merger timeline from March 31 to May 31. At the time, the attorney general still was collecting information about the merger, which would create one of the largest health care systems in the Upper Midwest.

Fairview owns the University of Minnesota Medical Center. Executives from the health systems are meeting on a weekly basis, they said, with U officials to discuss options for the sprawling hospital campus in Minneapolis.

The university opposes the merger and is seeking legislative support to regain control of the teaching hospital, but it's not clear how supportive lawmakers are of the idea.

"In the interest of ongoing cooperation with the Office of the Minnesota Attorney General, we have extended the target closing date for our merger until after May 31st and agreed to their request for 90 days' notice prior to closing at a future date," the health systems said in a statement.

In its statement, Ellison's office said it agreed "it is imperative for Fairview leadership to focus their attention on the critical issues facing the health system, including its declining financial condition and its relationship with the University of Minnesota."