Seven people have been injured after a United States fighter jet crashed on the deck of an aircraft carrier during operations in the South China Sea on Monday.

The F-35C Lightning II was trying to land on the USS Carl Vinson during routine flight operations in the South China Sea, US Pacific Fleet public affairs said.

"The pilot safely ejected from the aircraft and was recovered via US military helicopter. The pilot is in stable condition."

Three injured sailors were taken to Manila, Philippines, and four were treated onboard by medical personnel, public affairs.

"All three Med-Evacs are assessed as stable," it said. "Of the four sailors treated by on-board medical, three have been released."

The accident is being investigated.

It's unclear whether the aircraft fell into the sea or remained on the deck.

"The status of the aircraft is under investigation as are the factors involved in the mishap," US Pacific Fleet spokeswoman Brenda Way told the War Zone.

It's the second major accident involving an F-35 operating from an aircraft carrier.

In November, an F-35B Joint Strike Fighter crashed off the Royal Navy aircraft carrier HMS Queen Elizabeth during operations in the Mediterranean.

Extraordinary footage of the crash, taken from the carrier's surveillance cameras, was later leaked on social media.

It shows the jet approaching the ski jump as it prepares to take off, before slowing down as it reaches the ramp and toppling into the ocean.

The pilot can be seen ejecting from the $190 million aircraft just before it goes over the edge.

Early reports suggested the crash was the result of a plastic air intake cover mistakenly being left on one of the engines.

The UK Ministry of Defence said last month the wreckage had been pulled from the ocean, after an urgent recovery effort assisted by the US and Italian navies.

Defence officials had feared the jet's stealth technology could fall into Russian hands.

A photo of the wreckage surfaced on social media this week.

- By Frank Chung, news.com.au