One person died and more than a dozen swimmers were rescued from the ocean along the New Jersey Shore on Sunday amid warnings of dangerous rip currents over the Labor Day weekend, authorities said.

The National Weather Service had warned of "a high risk for the development of dangerous rip currents for the New Jersey and Delaware Beaches" since at least last Tuesday. The warnings will remain in effect through Labor Day into Monday evening, according to the weather service.

Three people were caught in a rip current while swimming in Beach Haven on Sunday afternoon, according to a statement from the Beach Haven Police Department.

Two of them were brought to shore safely, while a 22-year-old male was pronounced dead, according to the statement.

During the attempted rescue, about 15 lifeguards formed a chain and began a systematic search for the one victim who had been submerged, the statement said.

"Simultaneously, five lifeguards began a deep water grid search of the deeper water utilizing paddle boards and a JetSki," the statement said.

Additional support from local and state authorities helped locate the man who was pronounced dead, according to the police department.

A few hours later, five people who were swimming after lifeguards were off duty for the day were rescued from rip currents in Seaside Park, according to Andrew Casole, a spokesperson for the Seaside Park Police Department.

A 31-year-old man, swimming separately from the group, is missing, and search efforts are underway, said Casole.

At Belmar Beach, five other swimmers were rescued in the late afternoon, according to a statement from the Belmar Police Department. "The tide came, that's when they got pulled in," Chizzy Meremikwu, who witnessed the incident, told CNN affiliate WABC.

"They were in the back yelling, 'Help, help!' That's when everybody ran off the beach, calling for lifeguards," he said.

One swimmer was unresponsive and was transferred to Jersey Shore University Medical Center, according to Belmar police.

Two of the swimmers rescued were also transferred to a local hospital, according to the statement.