US still ready to talk to Iran: official

US leaders remain ready to negotiate with their Iranian counterparts but Tehran is still refusing President Donald Trump's overture to do so, a senior US official said Wednesday.

Trump and Secretary of State Mike Pompeo "have all made clear that we are ready to negotiate and to have those discussions," Brian Hook, the US special representative for Iran, told the Hudson Institute, a Washington think tank.

"There hasn't been any aversion to meeting with the Iranians," he added.

Hook stressed the goal was a "comprehensive deal" with Iran, based on a tough set of conditions Pompeo laid out in May.

The United States seeks a treaty ratified by Congress to replace the nuclear pact Trump withdrew from in May.

Washington insists such a deal should address Iran's ballistic weapons capabilities, its nuclear capacity and its "destabilising" and "malign" regional influence.

According to Hook, Iran's supreme leader Ayatollah Ali Khamenei, President Hassan Rouhani and Foreign Minister Mohammad Javad Zarif "have all indicated that they're not interested in talking. That's their position, we respect that."

Trump and Rouhani will both be in New York next week for the United Nations General Assembly.

The US president is to lead a Security Council meeting that will discuss Iran, among other topics.

While Rouhani will hold talks with his French counterpart Emmanuel Macron, no US-Iranian meeting has been announced.

The US re-imposed sweeping sanctions against Iran last month, and a new round of even harsher sanctions is set to go into effect November 5 targeting Iran's vital oil sector.