The US has imposed new sanctions on 11 companies and individuals it says are linked to the Islamic Republic's ballistic missile programme.

The Treasury Department confirmed the development less than 24 hours after international nuclear sanctions were lifted in a move Barack Obama insisted meant Tehran could no longer get its hands on a nuclear bomb.

The new sanctions come after the Obama administration delayed the action for more than two weeks during tense negotiations to free five American prisoners, according to people familiar with the matter.

"Iran's ballistic missile program poses a significant threat to regional and global security, and it will continue to be subject to international sanctions," acting Under Secretary for Terrorism and Financial Intelligence Adam Szubin said.

The annoucement came shortly before a televised address by the US President in which he admitted a recent episode in which US sailors strayed into Iranian territorial waters could have sparked an "international incident".

He also admitted that the US sailors, who were released promptly by Iran after the incursion, had “accidentally strayed into Iranian waters”.

But he said recent closer diplomacy between the two powers had borne fruit and that a crisis had been averted.

Mr Obama said Iran would not get its hands on a nuclear weapon and had now met key milestones as part of its nuclear deal.

Other diplomatic deals, including the unfreezing of Iranian fund and the exchange of prisoners were a result of closer relations between the two countries, he added.

“Iran will not get its hands on a nuclear bomb. The region, the United States, and the world, will be more secure,” he said in a statement delivered at the White House.

“Engaging directly with the Iranian government on a sustained basis for the first time in decades has created a unique opportunity, a window, to resolve important issues.”

Mr Obama said that Iran had “fulfilled key commitments” under last year’s nuclear deal, including filling in a plutonium reactor with concrete, removing two thirds of its uranium enrichment machines, and ditching large parts of its enriched Uranium stockpile.

The US president added that the country was subject to the strictest checks on its civilian nuclear programme ever negotiated in a deal.

In pictures: Obama's advisers Show all 3 1 /3 In pictures: Obama's advisers In pictures: Obama's advisers In pictures: Obama's advisers <p><b>Austan Goolsbee</b></p><p>The University of Chicago economist, who is an expert on tax policy and the role of technology in the economy, has been close to Obama for four years. After he met Canadian officials, the embassy wrote an internal memo questioning Obama's commitment to renegotiating the Nafta trade agreement, to add new protections for US jobs. According to the officials, anything said on the campaign trail "should be viewed as more about political positioning than a clear articulation of policy plans". Mr Goolsbee denied saying any such thing.</p> Getty In pictures: Obama's advisers Getty

He also warned that the US still denounced Iran on some aspects of its foreign policy: including alleged funding for militant groups in Syria and antagonisms between unspecified US allies in the Persian Gulf.

Iran’s policy towards Israel was also a source of criticism from America, he added.

Mr Obama was speaking after the announcement that four American prisoners in Iran would be released as part of a deal. He also confirmed the US was provide clemency to six Iranian-Americans held by US authorities.

Among the Americans release by Iranian authorities was Washington Post reporter Jason Rezaian.

That development comes after the lifting of sanctions on Iran that were imposed on account of its nuclear programme.

Other sanctions are still in effect against the country, however – including a newly imposed set against 11 Iranian companies and individuals on account of a recent ballistic missile test.