Asiana Airlines has said for the first time that pilot error was the "probable cause" of the deadly crash in San Francisco last July.

According to newly released report provided to the US National Transportation Safety Board, the airline said the pilots were flying too slow and failed to abort the landing in time before the Boeing 777 crashed into a seawall, in which three people were killed.

But Asiana still blamed the plane's automation and warning systems for contributing to the crash, along with what it called "a heavy workload" imposed on the pilots by air traffic controllers on the ground.

However, in a separate report submitted by Boeing, the company placed the blame squarely on the pilots, saying that the plane and all its systems were functioning as expected and did not contribute to the crash.

The two reports were parts of hundreds of pages of documents the NTSB will consider to determine the probable cause of the crash. The investigators are expected to finish the case before the anniversary of the crash on July 6th.