O’FALLON, Mo. — Leaders in Kansas City and St. Louis are urging people who partied close together at Lake of the Ozarks over the Memorial Day weekend to self-quarantine for two weeks.

Big crowds were reported at swimming pools, bars and restaurants at the popular central Missouri lake. Postings showed people without masks partying and swimming together, seemingly ignoring guidance from the U.S. Centers for Disease Control and Prevention, and from the state, to keep at least 6 feet apart.

St. Louis County Executive Sam Page called it “reckless behavior.” He asked the county’s health department to issue a travel advisory, citing concerns raised by residents and employers just as the county was beginning to reopen after weeks of shutdown caused by the virus.

St. Louis Mayor Lyda Krewson and Kansas City Mayor Quinton Lucas, both Democrats, took to Twitter to express their disappointment with the crowds at the lake, which draws from the metropolitan areas on both sides of the state, along with neighboring Arkansas, Illinois, Kansas and Iowa.

“If you were part of a group that didn’t socially distance or wear masks, please, for the health of your family, coworkers and friends, stay home for the next 14 days,” Krewson said in a tweet.

Kansas City Health Director Rex Archer echoed the call for a 14-day self-quarantine.