Minneapolis and St. Paul are reinstating indoor mask mandates, with mayors from both cities citing a rise in COVID-19 cases because of the highly contagious omicron variant.

Both mandates take effect at 5 p.m. Thursday. Minneapolis' order requires face coverings in "any indoor locations where members of the public may gather, visit or patronize." St. Paul's applies to businesses licensed by the city "at all times when social distancing of at least 6 feet is not maintained."

"We have to keep our city healthy and moving. Wearing a mask is an obvious next step to do both," Minneapolis Mayor Jacob Frey said in a statement Wednesday. "The surging numbers of cases and hospitalizations from the omicron variant demand immediate action to keep our residents healthy while making every effort to allow schools and businesses to remain safe and open across our Twin Cities."

After imposing face covering requirements at the onset of the COVID-19 pandemic, both mayors rescinded their mask mandates in June, as cases fell and vaccinations reached a larger share of the population.

Minneapolis and St. Paul resumed requiring face coverings in city-controlled buildings in August as the delta variant drove an increase in cases.

"Reinstating the masking requirement is an important step in keeping our communities safe amid the surge of COVID-19 cases in St. Paul," Mayor Melvin Carter said in a statement. "This, alongside our work to ensure St. Paul residents have the tools and access they need to get vaccinated are paramount to recovering from this pandemic and building toward our future."

Since July, COVID-19 cases have trended upward in Minneapolis, with community transmission exceeding 900 cases per 100,000 people, putting the city in the Centers for Disease Control and Prevention's (CDC) high-risk area category.

Ramsey County is reporting more than 500 new cases per 100,000 people per day and also is considered a high-transmission area by the CDC, according to St. Paul's news release.

The omicron variant accounts for nearly 70% of the cases in Minnesota. Gov. Tim Walz said Wednesday he is not instituting a statewide mask mandate, but he encouraged people to wear face coverings indoors.

"Even if we tried to do that, I'm not sure that folks would comply to the level we needed to," he said of a mandate, noting that local governments want to be included in such decisions.

The governor applauded the mask mandates in Minneapolis and St. Paul, and said several other jurisdictions may follow their lead.

"These are folks that know their community; they know what needs to be done. We know that masking is one of the big three that makes a difference in this, along with testing and vaccinations," Walz said.

Business leaders have worried that a patchwork of local laws can be confusing and difficult to enforce.

"We're concerned about the spike in COVID cases, as the longer the pandemic goes the worse it is for everyone in our community," B Kyle, president and CEO of the St. Paul Area Chamber of Commerce, said in a statement Wednesday.

"That being said, another mandate puts the burden of enforcement on businesses and their frontline workers. We're also concerned about the competitive disadvantage that comes with having different rules for different communities."

Minneapolis said it will continue to provide free masks to businesses and organizations. Citing the CDC guidelines, Minneapolis and St. Paul officials recommend that the public wear "high-quality" masks, such as N95 or KN95 masks, which offer more protection against omicron infection.

If that's not feasible, officials urge people to wear a well-fitting mask with at least two layers of tightly woven fabric, or layering a disposable mask under a cloth mask to boost effectiveness.

Institutions subject to the mask mandate in Minneapolis include retail stores, government buildings, stadiums, convention centers and service establishments as well as educational institutions, recreational facilities and service centers.

In St. Paul, the mandate will cover city-licensed establishments, including bars and restaurants that sell alcohol, certain entertainment venues, health and fitness centers and automotive businesses. St. Paul Public Schools also require masks in district buildings.

Both cities make exceptions for people while they eat or drink and will exempt young children (specified in Minneapolis as those younger than 2) and those with medical conditions that prevent them from wearing masks. The mandates also exempt athletes, performers and their support staff who are competing or performing indoors.

Fans at U.S. Bank Stadium in Minneapolis for Sunday's Vikings game must wear masks to comply with the city's mandate, Jeff Anderson, the team's vice president for strategic and corporate communications, said in a statement.

A violation of the mask mandates could result in a warning letter, a citation or misdemeanor prosecution. Businesses violating St. Paul's order also could face adverse licensing actions or penalties.

Staff writer Jessie Van Berkel contributed to this report.