US Secretary of State Antony Blinken considered on Tuesday that it was up to Iran to engage to resolve a deadlock over its nuclear program, accusing Tehran of facilitating what he called Russian "aggression in Ukraine."

"We continue to believe that with regard to the nuclear program, the most effective, sustainable way to deal with the challenge is through diplomacy," Blinken told a news conference during a visit to Athens.

"But at this moment, those efforts are on the back burner because Iran is simply not engaged in a meaningful way," he claimed.

Blinken said the US was committed, together with "Israel", to ensuring that Tehran "never acquire a nuclear weapon."

"In the meantime, of course, we've seen provision by Iran of drones to Russia to enable its aggression in Ukraine," he claimed.

The top US diplomat noted that "the door is always open to diplomacy going forward. A lot depends on what Iran says and does and whether or not it engages."

In late January, Blinken claimed that Iran rejected the chance last year to revive the 2015 nuclear deal, saying, "Unfortunately, they rejected what was on the table and had been agreed to by everybody. Their either wouldn’t move forward with it."

Read more: EU top diplomat: Deal with Iran only way to avoid nuclear Tehran

Western parties left negotiating table: Raisi

Touching on the 2015 nuclear deal, known as the Joint Comprehensive Plan of Action (JCPOA), Iranian President Ebrahim Raisi said on February 18 the Western parties "claim to be looking for an agreement, but what we see is that their actions do not correspond to their allegations."

He noted that "while Iran has declared its resolve to reach a good agreement, they do not follow suit. They have both gone back on their pledges and withdrawn from the JCPOA."

"They have also left the negotiating table and announced interest to pursue their goals on streets and instigate chaos than to engage in talks," the Iranian leader said, in reference to the recent Western-led riots that Iran has witnessed.

It is noteworthy that the original JCPOA was signed in 2015 by China, France, Germany, Iran, Russia, the UK, and the US, as well as the European Union. However, the US unilaterally withdrew in 2018 under the Trump administration and imposed its maximum pressure campaign on Iran, causing Iran to suspend the deal.

On-off talks to revive the JCPOA started in April 2021, but the indirect talks between the US and Iran have stalled for several months with Iran facing Western-led riots.

Since the beginning of talks, Tehran has been calling for guarantees that the US will not withdraw from the deal, lifting unlawful sanctions on Iran, and closing the file of political allegations made by the International Atomic Energy Agency (IAEA).

Read more: JCPOA at dead end, US' delay and withdrawal to blame: Ulyanov