The United States on Thursday announced sanctions on Iran's Ministry of Intelligence and Security which it accused of supporting terrorism, abusing the human rights of Iranian citizens and supporting the Syrian government's crackdown.

David Cohen, the US Treasurys under-secretary for terrorism and financial intelligence released the news in a statement. The move is the latest in a series of steps the US has taken to increase pressure on Iran over its nuclear program.

It bars Iranian ministry officials from travelling to America, blocks any property the Iranian intelligence ministry owns in the US and prevents American citizens or companies from dealings with the Iranian ministry.

Earlier, US Defense Intelligence Agency Director Lieutenant-General Ronald Burgess said Iran will respond if attacked but is unlikely to initiate or provoke a conflict.

As well, Burgess noted that despite the ratcheting up of sanctions, Iran is still unlikely to abandon its nuclear program.