china 's building activity in the spratly islands has infuriated neighbouring countries and the united states whose leadership accused the country of bullying others with its ` military muscle ' .
images reveal fiery cross reef virtually untouched by man-made structures in march 2014 but by march this year , it had been transformed into an artificial island which could be used for military operations .
they follow equally disturbing photographs released earlier this month showing a flotilla of chinese vessels dredging sand onto another artificially-built island on nearby mischief reef .