WASHINGTON - The US Department of State on Monday reaffirmed the willingness to engage with Tehran over the nuclear issue, downplaying new threats by the Iranian leadership to boost uranium enrichment.

State Department spokesperson Ned Price said in a daily press briefing that the United States is willing to engage the Iranians in the context of the P5+1, namely the United States, Britain, France, China, Russia, as well as Germany.

Tehran has yet to make a formal response to talks with P5+1, said Price. "We certainly hope the Iranians will be willing to be there."

Iran's Supreme Leader Ayatollah Ali Khamenei said earlier in the day that his country could increase its uranium enrichment up to 60 percent.

"We are not going to respond in specific terms to hypotheticals, to posturing," Price said in response to Khamenei's comments.

"What we are going to do is to reaffirm the proposition that is on the table," he added. "The United States is willing to meet with the Iranians to hash out these difficult complex questions."

Price also commended recent efforts made by the International Atomic Energy Agency (IAEA) to engage Iran on verification issues, while expressing concerns over Iran's ending implementation of Additional Protocol, which allows snap IAEA inspections.

The UN nuclear watchdog reached a temporary understanding with Iran over the weekend on the verification of the latter's nuclear program.

According to the IAEA, Tehran would cease implementing the Additional Protocol but would continue to allow "necessary monitoring and verification" for up to three months.

"There is less access, let's face it. But still we were able to retain the necessary degree of monitoring and verification work," IAEA chief Rafael Grossi told reporters after his visit to Tehran.

Grossi said this temporary agreement would allow other political discussions at other levels to take place.

Last week, the United States signaled its readiness to engage with Tehran over the nuclear issue, combining several goodwill gestures toward Iran.

The United States had eased travel restrictions on Iranian diplomats assigned to the UN and rescinded the so-called "snapback" UN sanctions against Iran unilaterally declared by the previous administration.

The Joe Biden administration repeatedly said that if Iran returns to full compliance with the 2015 Iran nuclear deal, formally known as the Joint Comprehensive Plan of Action (JCPOA), the United States would do the same. But Iran insisted its compliance would only take place once US sanctions were removed.

In response to the US withdrawal from the nuclear deal in 2018 and the reimposition of sanctions, Iran has suspended implementing parts of its obligations under the deal.