Heavy fighting continued in eastern Ukraine on Tuesday, following an admission late Monday by a Ukrainian general that the eastern front near Donetsk has effectively collapsed as troops suffer from exhaustion. Tuesday’s fighting was particularly heavy in Kupiansk in the north-eastern Ukrainian region of Kharkiv and in Kurakhove in the southern Donetsk region. In total, there have been 158 skirmishes over the course of the day, the General Staff in Kiev said in its evening report. In the Kupiansk area, a strategically important railway junction on the Oskil River, Russian troops reportedly atte…