US Defense Secretary Pete Hegseth said Tuesday that the coming days of the US-Israeli war with Iran "will be decisive," while admitting that Iran retains the ability to retaliate after suffering several weeks of massive US-Israeli attacks.

"Iran knows that, and there's almost nothing they can militarily do about it," he said at the Pentagon's press briefing on the war with Iran, the first in nearly two weeks, repeating claims that the Iranian authorities had been crippled.

"They will shoot some missiles; we will shoot them down," Hegseth said. The Pentagon chief paid an unannounced visit to US troops and bases in the Middle East over the weekend.

Asked about whether President Donald Trump will send US ground troops to Iran, Hegseth said, "We're not going to forgo any options."

Hegseth added that the Pentagon aims "to be unpredictable" when it comes to having US troops on the ground in Iran.

Gen. Dan Caine, the chairman of the Joint Chiefs of Staff, said at the briefing that US airstrikes are now focused on "interdicting and destroying the logistical and supply chains that feed" Iran's missile, drone and naval ship-building facilities.

Caine said that the US military had begun flying B-52 bomber missions over Iran's land territory for the first time, suggesting that Iran's air defenses have been seriously degraded.