The New York Air National Guard asked the U.S. Air Force on Wednesday for help in finding a multimillion-dollar military drone that crashed into Lake Ontario a day earlier.

The Syracuse-based 174th Attack Wing asked the Air Force to send an HC-130 search aircraft to look for the missing MQ-9 Reaper, according to Eric Durr, a spokesman for the New York state Division of Military and Naval Affairs, based in suburban Albany.

The cause of the crash during a training flight is being investigated.

The unmanned aircraft took off from Wheeler Sack Army Airfield at Fort Drum in northern New York and crashed early Tuesday afternoon in eastern Lake Ontario. The area where it crashed is about 19 kilometres from the lake's eastern shore and 56 kilometres from Fort Drum, home to the Army's 10th Mountain Division.

A U.S. Coast Guard helicopter and vessel looked for the aircraft Tuesday, but that search was called off because of bad weather. The Coast Guard wasn't searching for the drone Wednesday, Durr said.

He said the 174th doesn't have helicopters or other aircraft to conduct a search, so the unit sought help from the Air Force's Air Combat Command, which flies HC-130 aircraft used in search and rescue missions. Two upstate New York guard units fly versions of the C-130 but it wasn't immediately known if any of their aircraft would conduct the search.

The drone is used by the 174th to train Air Force pilots who use it on surveillance and attack missions globally. There were no missiles or other armaments aboard the 11-metre-long drone, said Col. Greg Semmel, commander of the 174th.

A spokeswoman for General Atomics, which makes the Reaper, says a new drone with a basic package of sensors costs $10 million to $12 million US.

Semmel said that the unit's drone flights have been suspended. No decision had been made on when they would resume, he said.