As Iran’s center for advanced nuclear centrifuges lies in charred ruins after an explosion, apparently engineered by Israel, the long-simmering conflict between the United States and Tehran appears to be escalating into a potentially dangerous phase likely to play out during the American presidential election campaign.

New satellite photographs over the stricken facility at Natanz show far more extensive damage than was clear last week. Two intelligence officials, updated with the damage assessment for the Natanz site recently compiled by the United States and Israel, said it could take the Iranians up to two years to return their nuclear program to the place it was just before the explosion. An authoritative public study estimates it will be a year or more until Iran’s centrifuge production capacity recovers.

Another major explosion hit the country early Friday morning, lighting up the sky in a wealthy area of Tehran. It was still unexplained — but appeared to come from the direction of a missile base. If it proves to have been another attack, it will further shake the Iranians by demonstrating, yet again, that even their best-guarded nuclear and missile facilities have been infiltrated.

Although Iran has said little of substance about the explosions, Western officials anticipate some type of retaliation, perhaps against American or allied forces in Iraq, perhaps a renewal of cyberattacks. In the past, those have been directed against American financial institutions, a major Las Vegas casino and a dam in the New York suburbs or, more recently, the water supply system in Israel, which its government considers “critical infrastructure.”

Some officials said that a joint American-Israeli strategy was evolving — some might argue regressing — to a series of short-of-war clandestine strikes, aimed at taking out the most prominent generals of the Islamic Revolutionary Guards Corps and setting back Iran’s nuclear facilities.