Authorities in North Myrtle Beach, S.C., remained engaged in a search effort on Thursday afternoon for a 21-year-old swimmer who went missing in the ocean the previous night.

The city shared in a Facebook update around noon, “Emergency personnel are actively involved in search operations both on the beach and in the ocean near 45th Avenue South in North Myrtle Beach. There’s a noticeable presence of emergency vehicles as crews continue their coordinated efforts. We urge the public to avoid this area if possible and adhere to instructions from First Responders.”

The search began Wednesday night after a report was received around 8:30 p.m. concerning two swimmers, aged 18 and 21, who were in distress, according to North Myrtle Beach Fire Rescue. Police and fire rescue swimmers responded immediately, successfully pulling the 18-year-old to safety on the shore.

Crews then searched throughout the evening in the area between 48th Avenue S. and Main Street. North Myrtle Beach Fire Chief Billy Floyd told News13 that a Coast Guard helicopter and on-beach police patrols were out all night.

The rescued swimmer was taken to the hospital as a precaution. As fire and police units continued searching along the shoreline, a Coast Guard helicopter conducted a grid search between the Windy Hill and Cherry Grove beaches, fire officials said in the post.

The rescue operation drew a crowd of onlookers to the beach, including Olivia Dean, who is in the area on vacation. Dean said she was inside, spending time with family, when she noticed flashing lights outside.

“I was like ‘hey guys, you should come outside, like, something’s going on,'” she said. “We didn’t really know what it was, and so we go outside and all the personnel, the EMT, fire were out there.”

She said it was a “scary” situation.

“You don’t know who it is,” she said. “It’s someone’s someone, and so it’s just a lot of prayers were going around in my family, and we just took a moment to just asked the Lord to just wash over them, just [give them] protection.”