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Roughly 60% of the naval arm of the Islamic Revolutionary Guard Corps is still in existence, the officials said, including fast-attack speed boats. On Wednesday, Iranian gunboats attacked several commercial ships in the Strait of Hormuz, shortly after President Trump announced he was unilaterally extending a ceasefire to allow more time for peace talks.

Iranian air power has been significantly degraded but not erased, said the officials, who requested anonymity from CBS News because they were not authorized to discuss the matters publicly.

About two-thirds of Iran's air force is still believed to be operational, the officials said, after an intensive U.S. and Israeli campaign that struck thousands of targets, including storage and production facilities.

Previously, the president and Defense Secretary Pete Hegseth have described the U.S. effort, called Operation Epic Fury, as essentially destroying Iran's military capacity.

The defense secretary has gone further in his public statements, saying, "Operation Epic Fury was a historic and overwhelming victory on the battlefield, a capital V military victory," Hegseth said at a Pentagon press briefing on April 8, shortly after Mr. Trump declared a ceasefire with Iran. He added, "By any measure, Epic Fury decimated Iran's military and rendered it combat ineffective for years to come."