A rail bridge over a main road leading into the eastern Ukrainian city of Donetsk has been destroyed by an explosion, blocking a key access route to the rebel-held city. An AP reporter saw the collapsed bridge in the village of Novobakhmutivka, where a rail line crosses over a highway leading out of the city of Donetsk. The road leads toward Slovyansk, a former stronghold of the pro-Russian insurgents that was retaken by Ukrainian troops on Saturday after an intense night of fighting. On Sunday, the rebels - most of whom have fled to Donetsk, the regional capital - promised to regroup and continue their battle against Kiev's forces. Pavel Gubarev, the self-described governor of the Donetsk People's Republic, promised "real partisan war around the whole perimeter of Donetsk."