The US will respond with lawful strikes against decision-makers who have been orchestrating attacks on American targets, US Secretary of State Mike Pompeo said in an interview with ABC on Sunday.
Mr Pompeo also said that intelligence assessment on Qasem Soleimani was clear.
"The intelligence assessment made clear that no action - allowing Soleimani to continue his plotting and his planning, his terror campaign - created more risk than taking the action that we took last week," Pompeo said in an interview on ABC's "This Week."
The US and Iran have been exchanging threats following the death of Major General Qasem Soleimani, the chief of the elite Quds force and one of the most influential figures in Iran, in a US airstrike at the Baghdad airport on Friday.
According to the Pentagon, Soleimani was responsible for the attack on the US embassy in Baghdad in late December and he was planning more attacks against US targets. Iran has promised to avenge Soleimani "at the right time and in the right place."