(Reuters) – U.S. health officials on Friday urged Americans to continue adhering to social distancing and other COVID-19 safety measures following rising concerns among experts that the reopening of the country’s economy could lead to a fresh wave of infections.

Officials from the U.S. Centers for Disease Control and Prevention (CDC) said that states may need to reimpose strict restrictions if COVID-19 cases spike.

“If cases begin to go up again, particularly if they go up dramatically, it is important to recognize that more mitigation efforts such as what were implemented back in March may be needed again,” said Jay Butler, the deputy director of infectious diseases at the CDC.

He said the public should continue to maintain 6 feet of social distance, wash hands regularly and wear protective facial coverings to reduce the risk of infection.

As the United States reopens its economy, a number of U.S. states, including Texas, Arizona and Florida, have relaxed social distancing guidelines in recent weeks. Many U.S. states also do not require residents to wear protective masks.

Most Americans support stay-at-home orders and said they always or often wear face coverings in public areas, according to results of an online survey conducted early May of over 2,000 adults in New York City and Los Angeles. Most also said they would feel unsafe if restrictions were lifted.

About half a dozen states are grappling with a rising number of coronavirus patients filling hospital beds, fanning concerns that the reopening of the United States may spark a second wave of infections.

A recent spike in cases in about a dozen states partially reflects increased testing. But many of those states are also seeing rising hospitalizations and some are beginning to run short on intensive care unit (ICU) beds.