LANSING, Mich. (AP) — Michigan Gov. Gretchen Whitmer on Friday imposed tighter restrictions in the Upper Peninsula, taking a step back in her phased reopening plan to try to stem a surge in coronavirus cases in the region.

The Democratic governor acted less than two hours before the Michigan Supreme Court declared unconstitutional a law that she has used to extend a state of emergency that underpins several virus-related restrictions. Whitmer said the ruling will not take effect for at least 21 days, and many of her measures will continue beyond that under alternative sources of authority.

Starting Oct. 9, people in the Upper Peninsula who can work remotely will be required to do so. Schools will have to require students and staff to wear masks in classrooms, and non-residential social gatherings and events at venues will be slightly smaller.

The change will leave the Traverse City region as the only part of Michigan still under phase five restrictions. Whitmer had not shifted any region back before.

Although the U.P. had very low numbers of confirmed cases from March through most of June, those numbers began to rise in late June, persisted at an elevated level through mid-September, then began sharply increasing. The governor’s office called the U.P.’s numbers the most concerning in the state.