A Marine went missing off the coast of Puerto Rico on Thursday, and the Coast Guard said on Thursday that it is looking for him after he went swimming in strong waves.

The Coast Guard reports that on Wednesday afternoon, 26-year-old Samuel Wanjiru was swimming in the “La Pared” beach area in Luquillo, on the western side of the U.S. territory close to San Juan, when he became distressed and dialed 911.

According to the statement, Wanjiru is a resident of Massachusetts and was on a family vacation to the island. In an attempt to obtain further details regarding Wanjiru’s military record, Military.com contacted the Marine Corps; however, a response was not received in time for publication.

The Coast Guard said that it dispatched an MH-60T Jayhawk helicopter to look for the Marine after receiving the 911 call. According to the statement, “multiple Office of Emergency Management offices in the area” and Puerto Rico police were involved in the search on Thursday, in addition to an HC-144 Ocean Sentry aircraft and MH-60T Jayhawk helicopters from Coast Guard Air Station Borinquen.

In a statement, Capt. José Díaz, the commander of U.S. Coast Guard Sector San Juan, stated that “this month has been deadly when it comes to beach drownings in the area of Puerto Rico.”

The Coast Guard assisted in the recovery of another injured swimmer off Isabela, Puerto Rico’s Montones Beach on the same day that Wanjiru vanished. He was found unconscious and subsequently pronounced deceased.

Since Tuesday, the National Weather Service has been warning swimmers that most of the island’s northern coastline had “a high risk of life-threatening rip currents.”

Since Tuesday, the National Weather Service has been warning swimmers that most of the island’s northern coastline had “a high risk of life-threatening rip currents.”

“People must understand that this is a serious enough situation that it will restrict our ability to use surface vessels for search and rescue operations without putting our crews and property in further danger,” Díaz issued a warning.

In a Facebook post offering updates on the search for Wanjiru, the State Agency for Emergency and Disaster Management of Puerto Rico also advised people “to NOT go to beaches this week because they are dangerous due to high tide.”

“We hope the families of those who lost loved ones to the sea find strength during this extremely difficult time,” Díaz said, sending out prayers and thoughts to them.