The United States prefers to resolve the situation with Iran diplomatically, said the US Secretary of State, Marco Rubio.
However, he noted that sometimes a diplomatic solution is impossible.
Rubio also said the talks with Iran were not particularly productive, calling Tehran's demands unacceptable and in some cases outrageous.
"The negotiations have not produced many results so far, because Iran's demands are not only unacceptable, in some cases they are outrageous, absurd and completely unrealistic," Rubio told reporters.
The US and Iran are not close to a breakthrough in the settlement, he added.