Russia has unveiled a new air defence system that its designers say will be used to form the basis of a new generation of missile-intercepting weapons. The S-400 can destroy targets travelling at up to five kilometres per second, including aircraft and medium-range ballistic missiles. Intercontinental weapons travel too fast to be intercepted. The S-400 air defence system is a modernised version of a Soviet-designed surface-to-air missile unit. Moscow is against Washington’s plans to deploy elements of an anti-missile defence shield in Poland and the Czech Republic.