London, March 16 : Russia is using secret 'decoy dart' missiles -- which they have refused to export to stop the West reverse-engineering them -- to strike Ukrainian targets, the US intelligence has claimed, Daily Mail reported. Mobile rocket launchers in Russia and Belarus are believed to be shooting Moscow's Iskander-M missiles while deploying decoy systems to fool Ukrainian air defence. These dart-shaped armaments, originally thought to be cluster bombs, have been seen on social media from almost the beginning of Russia's invasion, the report said. To hit key targets, the Russian military use Iskander missiles that have a range of up to 500 kilometers, around 300 miles, and carry a much more powerful warhead that can destroy big buildings and some fortified facilities, Daily Mail reported. The darts protect the Iskander rockets from air defence missiles by using heat-seeking and radar technology to fool defence systems, a US intelligence officer claims according to the New York Times. They confirmed the darts used and pictured work with the Iskander missiles. Some Iskander missiles were reportedly fired from the territory of Russian ally Belarus, which has served as a staging ground for the Russian invasion. Combating these short-range ballistic missiles has proved a difficult task for the Ukrainian air defence systems trying to prevent the onslaught that is targeting civilians in Kyiv and Kharkiv. First used in combat in 2008 in Georgia, the Iskander is designed to confound missile defences by flying on a low trajectory and manoeuvring in flight to strike targets as far out as 500km with an accuracy of 2-5 metres, according to the Center for Strategic and International Studies (CSIS). /IANS