New York | Two Indian students who went missing last week while swimming at a lake in the US state of Indiana are dead, local authorities have confirmed.

Siddhant Shah, 19, and Aryan Vaidya, 20, went swimming at Monroe Lake, roughly 102 km southwest of downtown Indianapolis, with a group of friends on April 15 but did not resurface, the USA Today newspaper reported.

After two days of intense searching, divers found their bodies 18 feet below the surface, investigators said on April 18.

Both students attended Indiana University's Kelley School of Business.

Shah and Vaidya were boating on a pontoon on April 15 when their group anchored to swim. Both men did not resurface and friends attempted to help them but were unsuccessful, the Indiana Department of Natural Resources was quoted as saying by the newspaper.

One of the men was struggling in the water when others jumped in to help, said Lt. Angela Goldman, a Department of Natural Resources representative.

Divers searched using sonar and scuba divers, and all day on April 16 under windy conditions, Goldman said. The lake was busy with boaters on April 15, which was sunny and warm.

But the next two days, cold rain and the wind changed the nature of the lake, which was mostly deserted.

"With 15-to-20-mph sustained winds, we're struggling with that," Goldman said.

"A lot of the technology we use that makes things more precise needs better conditions. When dealing with whitecaps and wind, our sonar is not as effective." Sycamore Schools confirmed that Vaidya is a 2021 graduate of Sycamore High School.

"The entire Sycamore community is heartbroken by this sudden loss. Aryan was very involved during his time at Sycamore, including as a member of the student council and DECA," WLWT television station, affiliated with NBC, reported.

"Aryan's death may raise different emotions for our staff and students. Some of these reactions may be mild, others may be more intense. Our Grief Response Team has been mobilised to respond," the school said in a statement