Satellite imagery indicates a sharp increase in construction activity during 2026 at Iran’s deeply buried Pickaxe Mountain nuclear site, according to a CNN report. The development comes as the United States is reportedly working on capabilities to strike the facility, which experts believe could withstand some of the most powerful bunker-busting weapons.

U.S. President Donald Trump has again threatened to attack Iran’s “Pickaxe Mountain.” Israeli intelligence reportedly believes that the Islamic Revolutionary Guard Corps has moved thousands of centrifuges to the site. CNN reported Wednesday afternoon that construction activity there has accelerated significantly during 2026, based on satellite imagery from the Center for Strategic and International Studies (CSIS) obtained by the network.

The CNN report said the construction surge has taken place amid the war. A team of experts examined satellite imagery covering a six-year period. “Pickaxe Mountain” is a nuclear facility that has remained untouched during the two most recent wars involving Iran. The site is located in the Zagros Mountains, near Iran’s Natanz nuclear facility, and Iran has spent the past six years excavating an underground complex deep beneath the mountain. Experts estimate that the facility could be capable of withstanding even the most powerful bunker-busting bombs.

According to CSIS experts, the underground facility was “likely designed to be a safe haven for Iran’s nuclear program.” The report also said there are indications that the United States is developing ways to attack the site, even though U.S. military forces concentrated on other categories of targets during the war that began February 28 and has now continued for six months.

CNN further reported that, only four days before the launch of Operation Epic Fury, the director of the Pentagon’s program for evaluating weapons for weapons of mass destruction signed a $1.2 million “emergency contract” to “repair a unique subterranean test facility at White Sands Missile Range” in New Mexico. The objective was to conduct a “live-fire test designed to validate classified capabilities against rapidly emerging threats.”

Three sources told CNN that the planned test was connected to the war in Iran. The sources specifically cited the need to develop a capability for attacking the deeply underground facilities that Iran has excavated at its greatest depths.