Trump made the announcement in a speech that detailed a more confrontational approach to Iran over its nuclear and ballistic missile programs and its support for extremist groups in the Middle East. (Photo: AFP/File)

Washington: US President Donald Trump struck a blow against the 2015 Iran nuclear agreement on Friday in defiance of other world powers, calling it 'one of worst' pacts in US history.

Trump made the announcement in a speech that detailed a more confrontational approach to Iran over its nuclear and ballistic missile programs and its support for extremist groups in the Middle East.

Trump said in an address at the White House that his goal is to ensure Iran's never obtains a nuclear weapon. 

Read: After UK and EU, China urges Trump admin to 'preserve' Iran nuclear deal

"Today I am announcing our strategy along with several major steps we're taking to confront the Iranian regime's hostile actions and to ensure that Iran never -- and I mean never -- acquires a nuclear weapon," Trump said.

While Trump did not pull the United States out of the agreement, aimed at preventing Iran from developing a nuclear bomb, he gave the US Congress 60 days to decide whether to reimpose economic sanctions on Tehran that were lifted under the pact.

That would increase tension with Iran as well as put Washington at odds with other signatories of the accord such as Britain, France, Germany, Russia, China and the European Union.