SANTIAGO, Chile — The Chilean Air Force said Wednesday it had located debris believed to be from a military cargo plane that crashed this week with 38 people aboard over a remote stretch of frigid sea between South America and the Antarctic.

The debris was found 19 miles south of where the plane last made contact, the Air Force said in a statement. The parts were being recovered for analysis to determine if they belonged to the Hercules C-130 cargo plane.

The Brazilian Ministry of Defense also said in a statement that one of its ships had recovered personal items and debris compatible with the plane, about 311 miles from the southern Argentine city of Ushuaia in Patagonia.

The aircraft, which was heading to a base in Antarctica, disappeared shortly after taking off late Monday from the southern city of Punta Arenas in Chilean Patagonia. The Air Force concluded early the next morning that the aircraft must have crashed, given the number of hours it had been missing.

"We will continue the search and hope for a better result," said Air Force General Eduardo Mosqueira, who has been leading the search effort.

The cause of the crash was unknown and officials acknowledged the slim chances of finding any survivors.

Earlier on Wednesday, the Chilean military sent fighter jets in an expanded search after large rolling waves in the icy Drake Passage and low clouds had complicated the mission the day before, authorities said.

The flight, which was carrying 17 crew members and 21 passengers, appeared routine until the moment it disappeared, Mosqueira said.

The region where the plane disappeared is a vast, largely untouched ocean wilderness of penguin-inhabited ice sheets off the edge of the South American continent with depths of 11,500 feet.

The military was using sonar-enabled Navy ships to detect irregularities at depth, Mosqueira said, adding it had established quadrangles to help organize the search. Ships from Argentina and Brazil were assisting, he said.