The Turkish army says it has no plans to stage a coup against President Recep Tayyip Erdogan and has threatened legal action against anyone who suggests otherwise.

The rare statement aims to quash speculation over the possibility of a coup while Erdogan visits the United States. The military said on its website such "baseless news" was hurting morale in its ranks without naming specific publications.

"It is out of the question to make concessions to any illegal action outside the command structure," it said.

The Turkish army, historically seen as a defender of secular principles, has ousted three elected governments and one prime minister.

The army's was power reduced through a series of measures after Erdogan became prime minister in 2003. Erdogan is due to return to Turkey on Sunday.