“President Trump has said he wants to sit down and negotiate this with Iran," the Democratic senator told Iran International.
"Iran having a nuclear weapon is unacceptable, so it's important that they be willing to resolve this,” the Maryland lawmaker added.
He was speaking before a defiant speech by Iran’s Supreme Leader on Monday in which the veteran theocrat appeared to double down on a hard line toward Washington.
Khamenei, 86,  ruled out any cooperation with the United States, saying every US president had demanded “Iran’s surrender” but failed.
“Only if the United States completely cuts its backing for the Zionist regime, removes its military bases from the region, and ceases interfering in its affairs, their request for cooperation with Iran—not in the near future but much later—could be examined,” Khamenei said.
Iran denies seeking nuclear arms and says its program is peaceful.
The United States held five rounds of negotiations with Tehran over its disputed nuclear program earlier this year, for which President Donald Trump set a 60-day ultimatum.
When no agreement was reached by the 61st day on June 13, Israel launched a surprise military offensive, followed by US strikes on June 22 targeting key nuclear facilities in Isfahan, Natanz and Fordow.
Senator Van Hollen has previously expressed skepticism of military efforts to deny Iran a nuclear bomb.
“I have long supported the goal of ensuring that Iran never obtains a nuclear weapon. But bombing is not, in my view, the best and certainly not the most sustainable way of achieving that goal,” he told the Arms Control Association in a speech in September.
Van Hollen has said the window of diplomacy is still open in his remarks in September and there should be a coordinated effort to reach an agreement.
“The United States, the E3 (France, Germany, and Britain) and Iran should move swiftly to restart negotiations on a pragmatic, effective nuclear agreement,” he said.