TEL AVIV—Six months after launching a 12-day war with Iran over its nuclear program, Israeli officials are raising the prospect of another clash over Tehran’s efforts to rebuild its arsenal of ballistic missiles.
Israeli Prime Minister Benjamin Netanyahu, speaking Wednesday at a graduation ceremony for Israeli air force pilots, said Israel was watching Hamas, Hezbollah and Iran as they rearm and would act if necessary. The country’s defense minister and the head of its air force, speaking at the same event, said Israel would move to prevent new threats.
“We are not looking for confrontations, but our eyes are open to any possible danger,” Netanyahu said.
The comments come as Netanyahu prepares to travel to the U.S. for a year-end meeting with President Trump. Israel’s assessment of Iran’s progress on ballistic missiles and the prospect of further military action will be on the agenda when the two leaders meet, an Israeli official said.
It is unclear how the Trump administration would receive the prospect of new strikes on Iran as it leans on Israel to solidify the U.S.-brokered peace deal for Gaza and resolve tensions with the new government in Syria.
Trump has repeatedly said U.S. bombing raids on key Iranian facilities this summer wiped out Iran’s nuclear program and opened the door to regional peace. U.S. officials have quietly expressed frustration with Israel’s readiness to turn to force. Trump has warned Iran against rebuilding its nuclear facilities, but not specifically about ballistic missiles.
“As President Trump has said, if Iran pursued a nuclear weapon, that site would be attacked and would be wiped out before they even got close,” White House spokeswoman Anna Kelly said when asked whether the administration would support an Israeli attack over the missile program.
Any Israeli strike would need at least a tacit signoff from Washington because Israel would need American help to defend it from the missiles Iran would likely launch in response.
Attacking Iran over its ballistic missiles would mark a significant tightening of Israel’s red lines toward the country. When Israel launched its surprise attack in June, its main target was Iran’s nuclear program, which it considers an existential threat.
Israel did set the destruction of Tehran’s conventional long-range weapons as a goal of the 12-day war, and afterward warned Iran that any attempt to rebuild either its nuclear or missile program would invite an attack. Drawing the line at missiles makes another war significantly more likely in the coming year, said Danny Citrinowicz, a former head of the Iran branch for Israeli military intelligence and now a senior Iran researcher at Israel’s Institute for National Security Studies.
“Israel never went to war over a conventional buildup. It would be a first,” Citrinowicz said. “We are forcing ourselves to preserve a red line that will force us to attack again.”
This shift, Citrinowicz said, is part of Israel’s new national security doctrine following Hamas’s surprise Oct. 7, 2023, attacks, under which Israel won’t hesitate to act on possible threats.
Gulf Arab states are also concerned about Iran’s missile program. But Iran, which lacks an effective air force, sees missiles as a cornerstone of its defense—especially with its nuclear program and regional allies Hezbollah and Hamas badly battered by two years of fighting with Israel.
Analysts say Iran is moving to restore its missile manufacturing capability while proceeding much more cautiously with its key nuclear sites.
Iran has a deep hole to climb out of after multiple rounds of Israeli strikes that took out missiles, launch platforms and machines needed to produce solid fuel.
Earlier in December, a U.S. special operations team boarded a ship in the Indian Ocean and seized military-related goods headed to Iran from China. Separately, the U.S. Treasury Department hit 32 individuals and entities across Europe, the Middle East and Asia for supporting Iran ballistic missile and drone production.
Satellite images taken by Planet Labs show Iran is rebuilding the missile production sites targeted by Israel in previous strikes, said Sam Lair, a research associate at the James Martin Center for Nonproliferation Studies, who studied the imagery.
Should Iran get its production facilities running at full capacity, it could produce hundreds of missiles a month, Lair said. The flurry of activity at these sites indicates Iran is likely already producing new missiles, but he said there wasn’t enough evidence to conclude that definitively.
“The Iranians appear to have reconstituted some capability to produce missiles, but are not where they were previously,” Lair said. “They are devoting resources to rebuilding those facilities, and they could get there again.”
Israeli and American media have been full of warnings from analysts, think tanks and politicians in Israel and the U.S. about Iranian efforts to rearm.
“The central thing from six months ago is not only that we acted to significantly degrade those programs, but we broke the barrier to attack Iran,” Eli Cohen, Israel’s energy minister and a member of Netanyahu’s Likud party, said this week on Army Radio. “The message to Iran is clear: If you try to rebuild the nuclear program or rearm with ballistic missiles, the state of Israel will attack.”
On Sunday, Sen. Lindsey Graham (R., S.C.) met Netanyahu in Jerusalem before giving interviews in Israel advocating an attack on Iran if necessary to stop its missile program.
“We cannot allow Iran to get back into the ballistic missile production business,” Graham said in an interview with I-24 News. “The next attack, if there is a next attack, will be focused on their ballistic missile capability.”
Iran launched heavy missile barrages against Israel last year, part of a tit-for-tat escalation that involved the first-ever direct strikes between the two longtime foes. The attacks overwhelmed Israeli defenses in some areas, while Iranian missile volleys during the war this summer grew increasingly successful and left dozens dead. But the attacks did little strategic damage.
Israel is concerned Iran could eventually produce thousands of missiles in the coming years, enough to overwhelm any defense. Netanyahu this week signaled concerns Iran could try to strike Israel first.
Analysts said it is unlikely Iran would attack Israel first given the regime is still weakened from the last war and is buckling under multiple crises at home, including a major water shortage and a currency in free fall. Tehran is also wary of provoking the U.S.
Iran is giving priority to rebuilding its missile capability to raise the cost to Israel of any future attacks, said Ali Vaez, Iran project director at the conflict-resolution organization International Crisis Group.
“The odds of a pre-emptive Iranian strike are near zero,” Vaez said. “The Iranians have realized that though their airspace is vulnerable, so is Israel’s.”
Security analysts said Israel’s thinking around a strike is influenced by what it sees as a short window of opportunity while Iran’s capacity to launch missiles is still degraded, its air defenses are weak and the regime is dealing with a number of challenges.
“We don’t want to wait for them to get stronger to attack us,” said Amir Avivi, a former senior defense official close to the current government. “We have to deal with this now and hit them while they are weak and the air corridor is open.”
Write to Dov Lieber at dov.lieber@wsj.com