President Donald Trump on Wednesday warned Iranian Supreme Leader Ayatollah Ali Khamenei that he should be “very worried” ahead of planned nuclear talks, as the president weighs military action amid rising tensions and signs Tehran may be trying to revive its nuclear program.

“I would say he should be very worried, yeah, he should be,” Trump told NBC News when asked whether Khamenei should be concerned. “As you know, they are negotiating with us.”

U.S. and Iranian officials are slated to meet Friday in Oman, which Iranian Foreign Minister Abbas Araghchi confirmed Wednesday. Iran pushed for the discussions to be moved from Turkey and has insisted they remain limited to its nuclear program. The United States has sought to broaden the agenda to include Tehran’s ballistic missile capabilities and support for regional proxy groups.

Experts told Jewish Insider that despite upcoming discussions, military intervention remains on the table. On Tuesday a U.S. F-35 fighter jet shot down an Iranian drone near the USS Abraham Lincoln in the Arabian Sea. Later that day, Iran’s Islamic Revolutionary Guard Corps attempted to stop and board a U.S.-flagged commercial tanker in the Strait of Hormuz before a U.S. destroyer intervened and escorted the vessel to safety.

During an interview on the Megyn Kelly Show, Vice President JD Vance said Wednesday that Trump “will try to achieve what he can through non-military means, but if he feels that the military option is the only option, he is going to choose that option.”

Several Arab and Muslim leaders reportedly lobbied the Trump administration not to walk away from the discussions after Iran demanded to change the venue and format. The administration “told the Arabs we will do the meeting if they insist,” one U.S. official told Axios, but added that they are “very skeptical.”

Satellite images released last week by Planet Labs PBC have also fueled speculation over whether Iran intends to restart its nuclear program after U.S. strikes on several sites in June. Trump confirmed that Iran was “thinking about starting a new site in a different part of the country,” but said the U.S. “found out about it.” 

“I said, ‘You do that, we’re going to do very bad things to you,’” Trump warned, stating that in the event Iran continued to pursue its nuclear ambitions, the U.S. would respond as it did before. “If they do, we’re going to send” B-2 bombers “right back and do the job again.”

Last month the president had cancelled meetings with Iranian officials and vowed on social media that Tehran would “pay a big price” for its violent crackdown on protesters in early January, stating that “help is on its way.” 

When pressed on whether the U.S. continues to back Iranian protesters, Trump said the administration’s position has not changed.

“We’ve had their backs,” said Trump. “If we didn’t take out” Iran’s nuclear sites, “we wouldn’t have peace in the Middle East, because the Arab countries could have never done that.”