Tensions between Iran and US have increased under the Trump administration. After he took office, US president Donald Trump has dealt a major blow to the 2015 Iran Nuclear Deal, signed by his predecessor Barack Obama, and five other world powers. The deal allowed for the lifting of major sanctions against Iran in exchange for a curtailment of its nuclear program. But Trump in 2017 ramped up the pressure on Iran with unilateral sanctions. He also called it the "worst deal" and "embarrassment" for Washington in his maiden speech to the UN General Assembly. Despite criticism from around the world, Trump declined to certify the agreement to the congress in mid-October, leaving the deal in a deep uncertain future.