WASHINGTON (AP) — Israeli President Isaac Herzog warned President Joe Biden on Wednesday of a mounting Iranian "challenge" as Tehran continues its brutal crackdown over widespread protests led by young Iranians and U.S. efforts to revive the Iran nuclear deal flounder.

At the start of an Oval Office meeting with Biden, Herzog noted it had been 40 days since the death of Mahsa Amini in Iranian security custody, which spurred the protests across Iran. He also noted that Iran was "moving toward" becoming a nuclear power and alluded to Tehran providing Russia with drones that are "killing innocent citizens in Ukraine."

"Today, the Iranian regime is crushing thousands of Iranian citizens— young men and women — who are demonstrating and simply pleading to have their own liberties," Herzog said. "I think the Iranian challenge will be a major challenge that we are discussing."

Israeli officials have made the case to Biden that reviving the 2015 nuclear agreement would not stop Tehran from achieving its nuclear ambitions and would destabilize the region. The Biden administration, however, until recently seemed determined to bring back the deal, which would provide Tehran with billions of dollars in sanctions relief in exchange for the country agreeing to roll back its nuclear program to the limits it set.

But the administration has sounded increasingly pessimistic about the prospects for the deal in recent weeks as Iran has shipped drones to Russia for use in its war against Ukraine and as it has responded with brutality to the women-led protests against the Islamic government that erupted more than a month ago.

White House officials have said in recent days they are not focused on diplomacy with Iran at the moment and are looking to support the protesters who have taken to the streets.

The demonstrations are the most sustained protests against the Islamic government in more than a decade. They erupted after morality police detained Amini last month for not properly covering her hair with the Islamic headscarf, known as the hijab, which is mandatory for Iranian women. Amini, 22, collapsed at a police station and died three days later.

Biden made no mention of Iran in his brief comments to reporters at the top of his meeting with Herzog. He congratulated Israel for a m aritime boundary agreement with Lebanon that is set to be signed on Thursday.

The agreement, coming after months of U.S.-mediated talks, marks a major breakthrough in relations between Israel and Lebanon, which formally have been at war since Israel's establishment in 1948. The agreement provides for the development of energy fields for the benefit of both countries.

"I think it's a historic breakthrough," Biden said. "It took a lot of courage for you to step up and step into it."

Herzog met on Tuesday with Secretary of State Antony Blinken and House Speaker Nancy Pelosi as part of his whirlwind visit to Washington.

"We are standing together against the dangerous, destabilizing and terrorizing actions that Iran is taking in the region and, as you've noted, well beyond the region," Blinken said during his appearance with Herzog.

Herzog's visit also comes as violence escalates in the West Bank. Israeli forces on Tuesday raided a stronghold of an armed group in the occupied West Bank's second-largest city, blowing up a bomb lab and engaging in a firefight, the military said. Five Palestinians were killed and 20 were wounded, according to the Palestinian Health Ministry.

Congressional leaders have invited Herzog to address a joint meeting of Congress as Israel prepares to celebrate the 75th anniversary of its founding next year. The date for Herzog's address has not been set.

The State of Israel was proclaimed on May 14, 1948. President Harry S. Truman recognized the new nation the same day.

In a letter extending the invitation, Pelosi and Senate Majority Leader Chuck Schumer said the two nations have shared "an unbreakable bond rooted in common security, shared values, and friendship."