The US has imposed fresh sanctions on Iranian companies and individuals over a recent ballistic missile test.

The new sanctions prevent 11 entities and individuals linked to the missile programme from using the US banking system.

The move came the day after international nuclear sanctions on Iran were lifted as part of a deal designed to prevent it developing nuclear arms.

Four American-Iranians were also freed in a prisoner swap as part of the deal.

Among them was Washington Post reporter Jason Rezaian. A fifth American freed separately.

The US said it had offered clemency to seven Iranians being held in the US for sanctions violations.

Negotiations over the prisoner exchange in December delayed the US Treasury's imposition of the latest sanctions, reports said.

'Significant threat'

They were triggered by Iran conducting a precision-guided ballistic missile test capable of delivering a nuclear warhead last October, violating a United Nations ban.

"Iran's ballistic missile program poses a significant threat to regional and global security, and it will continue to be subject to international sanctions," said Adam J Szubin, US acting under-secretary for terrorism and financial intelligence.

Earlier, Iranian President Hassan Rouhani hailed the lifting of sanctions imposed since 2006 over its nuclear programme as a "new chapter" in its relations with the world.

The US has imposed fresh sanctions on Iranian companies and individuals over a recent ballistic missile test.

The new sanctions prevent 11 entities and individuals linked to the missile programme from using the US banking system.

The move came the day after international nuclear sanctions on Iran were lifted as part of a deal designed to prevent it developing nuclear arms.

Four American-Iranians were also freed in a prisoner swap as part of the deal.

Among them was Washington Post reporter Jason Rezaian. A fifth American freed separately.

The US said it had offered clemency to seven Iranians being held in the US for sanctions violations.

Negotiations over the prisoner exchange in December delayed the US Treasury's imposition of the latest sanctions, reports said.

'Significant threat'

The new sanctions were triggered by Iran conducting a test last October of a precision-guided ballistic missile capable of delivering a nuclear warhead, in violation a United Nations ban.

Iran's ballistic missile programme "poses a significant threat to regional and global security, and it will continue to be subject to international sanctions" ,said Adam J Szubin, US acting under-secretary for terrorism and financial intelligence.

Earlier, Iranian President Hassan Rouhani hailed the lifting of international sanctions imposed since 2006 over its nuclear programme as a "new chapter" in its relations with the world.