Back-to-back shark attacks Saturday off Oahu left two men injured, one critically.

A 44-year-old Kailua man received critical injuries to both feet in a shark attack late Saturday morning off Lanikai Beach.

In the early evening, a second man, 32, was bitten at Waikiki, just offshore of the police substation on Kalakaua Avenue. He received serious injuries.

According to Emergency Medical Services, paramedics responded to 2425 Kalakaua Ave. at 7:20 p.m.

An officer at the police substation said the victim was a local man whose left foot was reportedly bitten. He said the injury was minor, so it was probably a small shark. The victim wasn’t able to identify the type of shark.

Emergency Medical Services described the trauma as serious.

At Lanikai Beach, the victim was swimming out to the Mokulua Islands without fins and was about 50 to 100 yards away from shore when the attack occurred, officials from the city’s Ocean Safety and Lifeguard Services Division said.

Dr. Brian Jones, 28, said he and a group of friends were preparing to launch their kayaks at a nearby beach access.

“I heard some screaming and commotion down the beach,” he recalled.

His roommate, Jaime Carrion, 34, said neighbors told them it was a tiger shark attack, so he warned his friends not to go in the water, and ran with Jones, a medical doctor, to help.

By the time they got there, the victim was being pulled out of the water, and lifeguards were placing a tourniquet on his wounds.

“You could see what the shark did,” Jones said. “He was missing the bottom half of his left leg and the right leg was barely hanging on. He was in pretty bad shape. He was going through a seizure a little bit, but they got him on the ambulance and he was still there (conscious).”

Fred Chen, 25, of Kapolei, said, “By the time he got to shore, he kind of stopped bleeding.”

Jones said an emergency medical technician was quickly on scene. “His friend was trying to calm him down, and said, ‘Breathe, breathe.’”

Carrion said: “It was extremely sad. I hope he made it.”

This was the second and third shark attacks in Oahu waters in eight days and the sixth and seventh in Hawaii this year. On Oct. 9, a 25-year-old North Shore surfer lost a portion of his left leg and a finger to a 13-foot tiger shark at a North Shore surf spot known as Leftovers.

On Saturday, a father and son on one-man canoes saw the injured man and brought him and a friend who was swimming with him to shore, Ocean Safety Lt. Tony Ho said.

EMS responded at about 11:40 a.m. , and reported the man was taken to the hospital in serious condition.

Rescue watercraft from the Honolulu Fire Department and Ocean Safety cleared the water a mile in each direction, and shark warning signs were posted.

Ho said lifeguards will likely reassess the beach closures at noon today.

Lifeguard Rod Alderton, who was involved in the rescue, said the victim was brought in at Beach Access 10 near 1408 Mokulua Drive at the far end of Lanikai Beach.

Barbara Lawson, 69, a former Kailua resident, said, “I came to pay my respects,” after learning about the attack on Facebook. She said she got goose bumps recalling the December 1958 fatal shark attack on Lanikai resident Billy Weaver, a student at Punahou School. She said she was at Lanikai Beach with many other community members when it happened, but Weaver bled out before they could get him to shore.

Timothy Sweeney, 37, swam in waters off Beach Access 10 despite the warnings.

“Today, it was definitely murky, so I tried to stay knee-deep,” said Sweeney, who regularly swims in the area.

Yana Panchenko, 38, of Russia, had planned to swim there, but changed his mind.

“I’m scared now,” he said.