China appears to be building hundreds of new silos to house intercontinental ballistic missiles, raising some questions about its intentions. To some experts Insider talked to, the huge silo fields look to be China’s answer to rivals that have a lot more nuclear weapons.

In recent months, analysts with the Federation of American Scientists and the Middlebury Institute of International Studies (MIIS)  relying on commercial satellite images have found that China is constructing what looks like around 250 new missile silos. It previously had only about 20 silos.

Silo construction is clearly visible and appears to be underway in Hami in Xinjiang province, Yumen in Gansu province, and Jinlantai in Inner Mongolia. The Hami site, which is still in the early stages of construction, is roughly 300 square miles and the Yumen site is around 700 square miles.

The silos are grouped but spaced roughly two miles apart in grid patterns, which is very different from the way China has approached silos in the past. The country’s older silos are scattered, isolated, and somewhat camouflaged.

Sharing a report on the findings, U.S. Strategic Command tweeted this week that “the public has discovered what we have been saying all along about the growing threat the world faces and the veil of secrecy that surrounds it.”

Silos are much more vulnerable than some alternative launch platforms because they do not move, making them easy to find and even easier to target, but with enough silos and modern missile technology, they can be advantageous.

A Lot More Silos

ICBM silo construction in China
ICBM silo construction (Planet Labs/Center for Nonproliferation Studies at MIIS)

Having a significant number of missile silos makes it more difficult for an adversary to eliminate a country’s nuclear weapons before it has the chance to use them, and it is not even necessary to fill them all with missiles.

Jeffrey Lewis, director of the East Asia Nonproliferation Program at MIIS, suspects that China will employ a “shell game” strategy, putting missiles in only some of the silos. The U.S. military pursued a similar strategy during the Cold War.