The head of the Atomic Energy Organization of Iran has defended the 2015 nuclear deal and warned the United States over a possible withdrawal from the agreement.

Ali Akbar Salehi said the failure of the accord will undermine the political credibility and the international image of the US.

He noted that Washington’s recent “delusionary, negative postures do not augur well” for keeping the deal intact.

Salehi stressed that the hard-won agreement is too precious to be allowed to be undermined or weakened.

He said Tehran’s faithful implementation of the deal has strengthened the Non Proliferation Treaty.

The remarks come as US President Donald Trump is to deliver a speech on Iran this week in which he is expected to decline to certify Iran’s compliance with the landmark agreement, and refer it to Congress.