Russian shelling killed four people in eastern Ukraine’s Donetsk region, authorities said Monday, as Moscow’s forces aim to push deeper into the war-battered region. Donetsk region Governor Vadym Filashkin said attacks late Sunday against the mining town of Siversk, which is flanked by Russian forces, had led to the deaths. “The city was shelled yesterday evening with multiple rocket launchers. It has now been established that four men aged 36 to 86 died as a result of this shelling,” Filashkin wrote on social media. Siversk, which had an estimated pre-war population of 11,000 people, has come…