According to an analysis of satellite images by Al Jazeera, Russian forces are fortifying the Crimean peninsula in anticipation of a Ukrainian attempt to recapture it. The images reveal that the Crimean border and surrounding areas have been transformed into a fortified barrier ahead of an expected spring counteroffensive by Ukrainian forces. An extensive network of trenches and defences has been constructed and now extends across the border villages of Crimea. Construction and expansion of several significant military bases also took place during the same period. The trenches in northern Crimea suggest Russia is acting to deter Ukraine from mounting a ground assault from the north, Ukraine’s only way in. Further south, the trenches and fortifications suggest Russia is expecting any successful breach of its first line of defence to move along two highways, the E97 and E105. Western allies have been squeamish about giving the Ukrainian government the go-ahead to invade Crimea, not least because Russian President Vladimir Putin has insinuated it might trigger the use of tactical nuclear weapons.