The US special envoy to Iran, Brian Hawk, said Tehran was planning attacks on US interests, prompting Washington to strengthen its presence in the Gulf region.
He accused Iran of seeking to create a crescent to dominate the Middle East "in Iraq, Syria, Lebanon and other countries," and said it had to choose between two things: the collapse of the economy or acting responsibly.
He said in an interview with the island on Wednesday that the Iranian regime is outlaw and threatens the interests of several countries.
The US official pledged that Washington would continue to press hard on Tehran, stressing at the same time that President Donald Trump is not seeking to change the Iranian regime.
He added that Iran's history says it does not return to the negotiating table without economic pressure or diplomatic isolation. He said Washington's policy toward Iran was appropriate, preventing it from accessing financial resources.
"We have weakened Iran's capabilities as well as the level of support for its allies," he said, adding that diplomatic language was not working with the Iranian regime "which has been encouraging violence for 40 years."
He explained that the current US administration wants a new agreement with Iran instead, which was concluded during the era of former US President Barack Obama.
"We do not believe that the agreement under Obama will prevent Iran from acquiring a nuclear weapon," he said.
Hawk's remarks coincided with the US Treasury's announcement of new sanctions on Iranian oil tankers and companies.
Earlier, US President Donald Trump said a meeting with the Iranian president in New York was possible. "Iran is a country with great potential and we don't want regime change."