POKROVSK, Ukraine (AP) – The U.S. defense chief has urged Ukraine’s allies to “move at the speed of war” to get more and heavier weapons to Kyiv while Russia cut off gas supplies to Poland and Bulgaria. Defense Secretary Lloyd Austin made the remarks Tuesday as Russian forces rained fire on eastern and southern Ukraine amid new fears that the fighting could spill over the country’s borders. On Tuesday, explosions rocked the separatist region of Trans-Dniester in neighboring Moldova. Just across the border in Russia, the Belgorod regional governor says an ammunition depot was on fire early Wednesday after several explosions were heard. Poland and Bulgaria say the Kremlin is cutting off natural gas supplies starting Wednesday, the first such actions of the war.