JD Vance has said the US is “not at war” with Iran – but is with its nuclear weapons program, holding out a position that the White House hopes to maintain over the coming days as the Iranian regime considers a retributive response to Saturday’s US strike on three of its nuclear installations.

In an interview Sunday with NBC News’ Meet the Press, the US vice-president was asked if the US was now at war with Iran.

“We’re not at war with Iran,” Vance replied. “We’re at war with Iran’s nuclear program.”

But Vance declined to confirm with absolute certainty that Iran’s nuclear sites were completely destroyed, a position that Donald Trump set out in a Saturday night address when the president stated that the targeted Iranian facilities had been “completely and totally obliterated” in the US strikes.

Vance instead said that he believes the US has “substantially delayed” Iran’s ability to develop a nuclear weapon.

“I’m not going to get into sensitive intelligence about what we’ve seen on the ground there in Iran, but we’ve seen a lot, and I feel very confident that we’ve substantially delayed their development of a nuclear weapon, and that was the goal of this attack,” Vance said.

He continued: “Severely damaged versus obliterated – I’m not exactly sure what the difference is.

“What we know is we set their nuclear program back substantially.”

An Iranian member of parliament claimed on Sunday that the Fordo enrichment plant, the focus of seven B-2 bombers armed with 14 premier bunker-busters from the US arsenal, was not seriously damaged.

Those bombers returned to Missouri on Sunday.

Separately, Bloomberg News said satellite images of the site undermined the Trump administration’s claims that Iran’s underground nuclear sites at Fordo and Natanz had been destroyed.

Satellite images distributed by Maxar Technologies showed new craters, possible collapsed tunnel entrances and holes on top of a mountain ridge. But the main support building at the facility remained undamaged, the report said.

Maxar said in a statement that images of Natanz showed a new crater about 5.5 meters (18ft) in diameter over the underground facility – but they did not offer conclusive evidence that the 40-meter-deep nuclear engineering site had been breached.

The chair of the joint chiefs of staff, Gen Dan Caine, said at a Pentagon briefing on Sunday: “Final battle damage will take some time, but initial battle damage assessments indicate that all three sites sustained extremely severe damage and destruction.”

Nuclear non-proliferation analysts are conflicted on whether the strikes will be effective in bringing Iran to the negotiating table or convince them to move more decisively toward enriching uranium stockpiles to weapons-grade, assembling a bomb, and manufacturing a delivery system.

In a statement to Bloomberg, Darya Dolzikova, a senior research fellow at the Royal United Services Institute, said there were slim prospects that the US entering the war would convince Iran to increase International Atomic Energy Agency (IAEA) cooperation. The nuclear watchdog has said it is not sure where Iran’s 400lb stockpile of 60% uranium is.

“The more likely scenario is that they convince Iran that cooperation and transparency don’t work and that building deeper facilities and ones not declared openly is more sensible to avoid similar targeting in future,” Dolzikova said.

Iran’s foreign minister, Abbas Araghchi, said he planned to fly to Moscow to meet with Russia’s president, Vladimir Putin, on Monday morning for consultations. Separately, Israel’s prime minister, Benjamin Netanyahu, said his forces were progressing toward its goal of destroying Iran’s nuclear and ballistic missile threats.

“We are moving step after step to achieve these goals. We are very, very close to completing them,” he said.