A protester holds up a sign during a Senate appropriations committee hearing on US President Donald Trump's funding request for the defense department, in Washington, DC, on Tuesday. ERIC LEE/REUTERS

The administration of United States President Donald Trump appears to be shifting Washington's approach with Tehran from military threats to economic pressure, as the contentious reopening of the Strait of Hormuz drags on despite Iran signaling that an agreement with Oman is on the horizon.

Trump told US-based news outlet Axios on Sunday that Washington was "only semi-negotiating" with Tehran and stressed that Iran is in "very bad shape" economically.

"We are just watching Iran with its huge inflation and the fact they have no money," Axios quoted Trump as saying.

He said the US blockade has exacerbated Iran's economic crisis, adding that with oil down to slightly over $75 a barrel, consumers in the US are feeling less pain from the conflict.