In Ukraine's restive east, artillery explosions ring out all night: international monitors there record dozens of shell bursts every evening. The ceasefire between Kyiv and the Russian-backed separatists is fraying badly.
The flare up in fighting began sporadically in July. But now, Ukraine and its western allies are observing a more worrying development: a massive build-up of conventional Russian forces in Crimea and along the countries’ shared border.
