GRAND CANYON, Arizona (ABC4) — A hiker was pronounced dead after he fell ill during a “rim-to-rim” hike at Grand Canyon on Saturday, according to the National Park Service.

Ranjith Varma, 55, of Manassas, Virginia, reportedly fell ill during his hike from the South to North Rim of the Grand Canyon.

NPS officials said a call came in just before 2 p.m. on Sept. 9, regarding a hiker in distress, identified as Varma, on the North Kaibab Trail around one mile south of Cottonwood Campground.

Officials said that soon after, Varma became unresponsive and bystanders started CPR. Search and rescue personnel responded to the call via helicopter, which used “special maneuvers” to gain access to Varma.

After assuming care of Varma, rescue personnel gave advanced life support efforts and attempted to resuscitate him, but their efforts were unsuccessful and Varma was pronounced deceased.

Officials said that in the summer, temperatures on exposed parts of the trail can reach over 120 degrees Fahrenheit in the shade. Park rangers strongly advise not hiking in the inner canyon during the heat of the day, between the hours of 10 a.m. and 4 p.m.

“Be aware that efforts to assist hikers may be delayed during the summer months due to limited staff, the number of rescue calls, employee safety requirements, and limited helicopter flying capability during periods of extreme heat or inclement weather,” NPS officials stated.

Here are some hiking tips and backcountry updates, including trail closures and restrictions, provided by the NPS.

NPS is conducting an investigation into this incident in coordination with the Coconino County Medical Examiner.

No further information is available at this time.