The United States is sending additional troops to the Middle East in response to mounting concerns over Iran, which have escalated since attacks on two oil tankers in the Gulf of Oman.
The US military on Monday released images it says bolster its claim Iran is behind the attacks - but Iran continues to deny responsibility.
The new US deployment would be in addition to a 1500 troop increase announced last month in response to tanker attacks in May that the US also blamed on Iran.
The stand-off comes more than a year after President Donald Trump announced Washington was withdrawing from a 2015 nuclear deal.
Iran said on Monday it would soon breach limits on how much enriched uranium it can stockpile under the deal, which a White House National Security Council spokesman described as "nuclear blackmail."
The move further undermines the nuclear pact also signed by Russia, Britain, Germany, China and the European Union, but Iranian President Hassan Rouhani said the collapse of the deal would not be in the interests of the region or the world.
Rouhani said Iran would not wage war on any nation.
"Those facing us are a group of politicians with little experience," Rouhani said in a speech broadcast on state TV.
"Despite all of the Americans' efforts in the region and their desire to cut off our ties with all of the world and their desire to keep Iran secluded, they have been unsuccessful."
Rouhani also said on Monday that European nations still had time to save the accord.
Meanwhile US Secretary of State Mike Pompeo has spoken to officials from the North Atlantic Treaty Organisation, China, Kuwait, South Korea, Britain and other countries to share its evidence of Iran's involvement in the attacks on the Norwegian and Japanese tankers.
Australian Associated Press