MOSCOW–A strong earthquake measuring 6.8 shook southwestern Siberia in Russia on Sunday but caused no casualties or serious damage, the Russian emergencies ministry said. The quake’s epicenter was recorded at 1:20 p.m. local time (0620 GMT) in the republic of Tuva about 107 kilometers (66 miles) from the town of Kyzyl, which saw tremors of a similar magnitude on Dec. 27. The remote and scarcely populated republic on the Mongolian border is one of Russia’s most seismically active regions along with its Pacific Ocean coast. The regional emergencies ministry said the quake was felt throughout the Tyva and neighboring regions but caused no casualties or resulted in any serious structural damage, the RIA Novosti news agency reported. But several locals reported their apartment windows breaking and books and other items falling off shelves, with a series of tremors lasting four or five minutes. “My photographs and pictures started falling off the walls,” a resident of the town of Novokuznetskaya told RIA Novosti. The ground also shook in the nearby republic of Kemerovo to the northwest and several other regions, news reports said. “I live on the eighth floor. At first I though I was not feeling well. Then I realized that it was an earthquake,” one woman in Kemerovo told the news agency. The reading was based on the open-ended Moment Magnitude scale used by U..S seismologists, which measures the area of the fault that ruptured and the total energy released.