PHILADELPHIA (CBS) — Philadelphia health officials are recommending city residents stay away from beaches over the 4th of July holiday to avoid coronavirus exposure. Health Commissioner Dr. Thomas Farley says the biggest rise in COVID-19 cases is in teenagers and people in their 20s.

The young people diagnosed appear to have been exposed at the beach, but Dr. Farley says that doesn’t necessarily mean on the beach. They are being exposed at beach bars or from staying at houses where they are in close contact with each other.

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“We’re recommending people to stay away from that right now, that appears to be the hot spot, these beach places,” Dr. Farley said. “I know people want to go down there over the 4th of July weekend and I appreciate that but that appears to be the most dangerous place to be right now. So we recommend people stay here in Philly.”

Philadelphia has also scaled back its green phase of reopening that was scheduled for this Friday. The city announced the changes Tuesday afternoon.

Under the new restricted green phase guidelines, indoor dining and gym facilities will remain closed until at least Aug. 1, but other low-risk activities will be allowed to reopen Friday, July 3. Those activities include museums, libraries, indoor shopping malls and outdoor gatherings up to 50 people.

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Casinos are also allowed to reopen under strict guidelines — no food, beverages or smoking are allowed.

Dr. Farley tells CBS3 the increase in new coronavirus cases played a roll in the tough decision to step back from moving to the green phase.

He says other cities across the country opened too early and recklessly.

Health officials will be monitoring the virus in the city on a week-to-week basis and in order to reopen they are going to look closely at whether the case rate is rising or falling and also if people are following requirements issued by officials, including wearing masks.

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WATCH THE VIDEO ABOVE FOR THE FULL INTERVIEW WITH PHILADELPHIA HEALTH COMMISSIONER DR. THOMAS FARLEY.

Janelle Burrell