By Pavel Polityuk KYIV (Reuters) – Ukraine urged its allies on Friday to send more weapons as its forces dug in to slow Russia’s military advance through the eastern Donbas region, while a belligerent Moscow warned Western nations of consequences for their reprisals over its invasion. Signalling that the Kremlin was in no mood for compromise, President Vladimir Putin said continued use of sanctions against Russia risked causing “catastrophic” energy price rises. Putin’s top diplomat Sergei Lavrov clashed with his Western counterparts at a G20 meeting, where they urged Russia to allow Kyiv to s…