Military action against North Korea is “an option on the table”, US Secretary of State Rex Tillerson has said during a visit to South Korea, the BBC reports.
The policy of “strategic patience” had ended, he said, and the US was exploring a new range of diplomatic, security and economic measures.
He also defended the deployment of a US missile defence system in South Korea – a move that has angered Beijing.
Seoul and Washington say the system is needed to defend against North Korea.
Mr Tillerson spoke shortly after visiting the demilitarised zone which divides the two Koreas.
He arrived in South Korea from Japan, where he said that 20 years of efforts aimed at persuading North Korea to abandon its nuclear ambitions had failed.