Retired Army Gen. Jack Keane called Russia's threat to shoot down U.S. aircrafts in Syria "rubbish."

"That's rubbish," he said. "They're not going to shoot at U.S. airplanes. They're not going to take on the United States. They have very limited capability in Syria by comparison to U.S. capability."

Keane's comments came during an interview on Fox News' "Fox & Friends."

Russia warned that planes flying in Syria, west of the Euphrates River, would be considered targets after the U.S. Navy shot down a Syrian warplane, according to Fox News.

Keane, a retired four-star general added: "That's just more talk out of them. It's bluster."

The Hill noted Moscow also is demanding a full U.S. account of its decision to shoot down the Syrian jet Sunday