A senior Iranian commander has dismissed the rhetoric of threat used by Washington in stating that the United States will keep all options open if talks over Tehran’s nuclear program fail.

Iranian Armed Forces' Chief of Staff Major General Hassan Firouzabadi told reporters in Tehran on Saturday that the US issuing of threats was like firing an "empty cannon," adding that Washington was acting like a "paper tiger" when it threatened that all options are on the table with respect to Iran.

Firouzabadi said the United States, under the administration of former President George W. Bush, invaded Iraq and had plans to attack Iran as well, but fear of the Islamic Republic’s crushing response dissuaded Washington from going on with the plot.

The commander made the remarks following comments by White House spokesman Josh Earnest that Washington is keeping "all options open" if talks between Iran and the P5+1 group over Tehran's nuclear program fail.

Meanwhile, Deputy Chairman of the Chiefs of Staff of the Iranian Armed Forces Brigadier General Masoud Jazayeri also dismissed the rhetoric coming out of Washington.

He said Iran will make enemies regret any military attack against the Islamic Republic.

Jazayeri said the Western side seeks to make excessive demands in the course of the nuclear negotiations to gain concessions but, he stressed, Tehran will never cave in.

The US threat against Iran comes as negotiators from the Islamic Republic and the P5+1 group in Vienna are making a last-ditch effort to hammer out the remaining differences over a final nuclear deal.

The talks between Iran and the five permanent members of the UN Security Council – the United States, France, Britain, China and Russia – plus Germany could stretch into the weekend.