Moscow, May 23 (Reporter) Over 20 explosions was heard in the center of Belgorod, a Russian city some 40 km north of the border with Ukraine, amid a reactivated missile warning alert, Russia's RIA Novosti reported on Thursday. In the center of Belgorod, near Cathedral Square, several dozens of blasts were heard against the background of a missile warning siren which had been turned on again, said the report. About 15 minutes earlier, a siren was sounded throughout the city, followed by a spell of explosions...////...