U.S. President Donald Trump said Iran has not agreed to a deal to end the ongoing war because its leadership is “strong” and “proud,” but insisted that Tehran will ultimately have “no choice” but to reach an agreement.

Axar.az reports, in an interview with NBC News, Trump said negotiations with Iran remain difficult but unavoidable.

“They’re strong, they’re proud, there are things they never thought they’d be doing that they’re going to have to do. They’ve got no choice, and it takes a little while,” Trump said.

He added that despite continued Iranian capabilities, U.S. strikes have significantly reduced their arsenal.

“I would say percentagewise, maybe 21%-22% of their missiles. It’s a lot of missiles, but it’s not what it was when we first attacked,” he said.

Trump also claimed that U.S. operations have severely degraded Iran’s military infrastructure.

“Most of the drone factories have been knocked out, most of the launching pads have been knocked out, and most of the missile manufacturing areas have been knocked out. But they still have capacity. They have some missiles, they have some drones,” he said.

The president emphasized that reaching a settlement would take time, dismissing calls for a quick resolution.

“It takes years to do these things,” Trump said. “These people have been fighting for 47 years. They’ve been killing Americans.”

He added that comparisons to other conflicts are misplaced, saying, “I’m moving very fast. I’m in three months. You know, Vietnam lasted 19 years. I’m into my third month.”

Trump’s remarks come as U.S. and Iranian officials continue indirect negotiations following months of conflict and intermittent ceasefires in the region.