WASHINGTON - Washington poured scorn on a threat by Iran to send warships close to the US coast, saying curtly on Wednesday that Tehran's navy does not have what it takes.

Iran, at odds with the United States and other governments over its nuclear program, raised eyebrows with the prospect set out on Tuesday by the Islamic Republic's navy chief.

"Like the arrogant powers that are present near our marine borders, we will also have a powerful presence close to American marine borders," Rear Admiral Habibollah Sayyari said, according to the official IRNA news agency.

White House spokesman Jay Carney dismissed the idea in a one-sentence reply to a reporter's question.

"We don't take these statements seriously, given that they do not reflect at all Iran's naval capabilities," Carney said.

Sayyari - whose declaration came just weeks after Turkey said it would host a NATO radar system to help spot missile threats from outside Europe, including Iran - gave no details of the timing or size of such a naval deployment.

The navy is vital for Tehran due to the Gulf's importance as a route for Iran's oil exports but it "is outdated and in need of substantial modernization," according to the GlobalSecurity.org think tank.

"For the present, Iran's naval capacity remains limited and barely supports its status as essentially a coastal defense force," GlobalSecurity.org said on its website.

The United States and Israel have not ruled out using force against Iran if diplomacy fails to prevent it from getting nuclear weapons. Iran insists its nuclear program is purely peaceful and largely for the generation of electricity.