On September 25th, for the second time in the last three months, China test fired one of its new DF-31B ICBMs (Intercontinental Ballistic Missiles). This missile has a max range of 10,000 kilometers. The DF-31B is a minor upgrade of the DF-31A and both of the recent tests were apparently successful. This is all part of a two decade effort to produce a Chinese ICBM that is competitive with the American Minuteman.
In the early 1990s China put the first DF-31 into service, sort of. The DF-31 only had its first successful launch in 2000. It's now believed to have a reliable and accurate guidance system, as well as a third stage that carries three 50 kiloton warheads. Only about a dozen DF-31s are in service, plus about a dozen DF-31As and a growing number of DF-31Bs. For a long time most of these appeared to be aimed at European Russia but now the main target is the United States at least according to Chinese media, which keeps repeating this.
DF-31 was China's first solid fuel ICBM (and had a range of over 8,000 kilometers) and roughly equivalent to the 30 ton Minuteman I (entered service in 1962 with a range of 9,900 kilometers). The DF-31 weighs about 41 tons and is 20 meters (62 feet) long and 2.25 meters (7 feet) in diameter. It was designed for use on submarines, land silos, and mobile launchers. The mobile version would halt at those "parking lots in the middle of nowhere" visible in satellite pictures of Qinghai province. These pictures show the DF-31 stored in a TEL (transporter, erector, launcher) vehicle. Driving these vehicles along special highways in remote areas provides more protection from counterattacks than using a reinforced silo. Eventually the improved DF-31A appeared, with multiple warheads and more range. which enabled it to cover most of the United States).
China is believed to have over 400 nuclear warheads, most of them installed on ballistic missiles. Only a few dozen of these missiles can reach the United States. These include the older (and about to be retired) DF-5, plus the newer DF-31A/B and DF-41. About two thirds of Chinese nuclear warheads are believed to be in missile warheads, most of them DF-21s and these will be replaced by DF-26Cs. Normally the nuclear warheads are stored separately and mated to the missiles only for actual use or the occasional training exercise. In 2009 China announced that its nuclear armed ballistic missiles were not aimed at anyone. Like most countries, China has long refused to say who its nuclear armed missiles are aimed at. Most of those missiles only have enough range to hit Russia or India, or other nearby nations. For a long time most were very definitely aimed at Russia, which had rocky relations with China from the 1960s to the 1990s. But after the Soviet Union dissolved in 1991, the new and much smaller Russia became friendlier with the wealthier (more capitalist but still run by communists) China. Relations between China and India also warmed up, then went into a deep freeze during the past decade.
For the last two decades China has had about two dozen DF-5 ICBMs nominally in service because they can reach the United States. Few of these are believed to be operational because of reliability and maintenance problems. The U.S. has since installed 18 ICBM interceptor missile systems in Alaska. These are to deal with North Korean missiles but could also destroy Chinese missiles headed for the western United States. Thus it makes sense for China to simply say that it is not aiming any of its missiles at anyone. Modern guidance systems can be quickly (in less than an hour) programmed for a new target, so it doesn't really matter that, normally, the missiles have no target information in them. The DF-5s, moreover, are liquid fueled and the considerable activity required to ready them for launch can be detected by spy satellites.
The DF-5s are being replaced by the solid fuel DF-41s, which can be moved, erected, and launched from a special truck. With a 15,000 kilometer range they can reach all of the United States. The third stage multiple warheads each with an explosive yield of at least 100 KT. The DF-41s appear similar to the American 36 ton Minuteman III (a 1960s design that has been much upgraded since then).