A 49-year-old Methuen man has died and a 47-year-old Methuen woman was listed in critical condition after several swimmers were rescued — some by a good Samaritan visiting from Boston — from a rip current Sunday off Seabrook Beach in New Hampshire, officials said.

The pair from Massachusetts were both given CPR and sent to nearby hospitals for treatment, according to a statement from the New Hampshire State Police on Sunday night. Officials did not provide further information about the victims’ identities.

Several police departments responded to a call around 12:30 p.m. reporting six swimmers “struggling in the water’’ off the beach near 131 Ocean Drive, according to a Sunday afternoon statement from deputy chief Brett Walker.

Four of the six swimmers were not injured, but two swimmers were unconscious when they were brought to shore, according to State Police.

“At this time it appears that choppy water conditions may have been a factor in this incident; however, all aspects remain under investigation,’’ State Police said.

Matt Tomaszewski, a 29-year-old from Boston, told the Globe in a phone interview Sunday night that he was visiting with his family, sitting on an Ocean Drive porch overlooking the beach, when he heard people in the water screaming for help.

He ran out with his father and then swam into the water by himself, and helped two people to shore using a paddle board.

“I got them both on the board. . . and pushed with everything I had,’’ he said.

He said he tried to help a third man, who appeared to be unconscious, but a large wave swept the man out of sight.

Tomaszewski said that even though he is athletic, “nothing could have prepared me for that.’’

“It was the toughest thing I’ve ever been through,’’ he said.

Resuscitation efforts on the two swimmers were still in progress when they were taken to local hospitals, according to Kassandra Lee, a dispatcher at the Seabrook Fire Department.

The Methuen woman was taken to Portsmouth Regional Hospital with life-threatening injuries, State Police said. The Methuen man — who Walker said was the last swimmer rescued, at 12:59 p.m. — was taken to Anna Jaques Hospital in Newburyport.

State Police Marine Patrol, the US Coast Guard, the Seabrook police and fire departments, and the Hampton Fire Department all responded to the incident.

Rescue efforts were also assisted by Hampton Beach lifeguards, who responded with a rescue boat and jet skis, according to Walker. Seabrook Beach, which is not staffed with lifeguards, is just south of Hampton Beach.

The scene was cleared at 1:40 p.m., Lee said.

Shortly after the rescue, Seabrook police urged visitors not to swim at the beach due to “dangerous currents.’’ Andrew Barresi, a Coast Guard spokesman, said Sunday night that the strong currents were indeed a rip tide.

Lucas Phillips can be reached at lucas.phillips@globe.com.