MOSCOW—Russia sent two nuclear-capable strategic bombers on a training mission over Belarus for a second straight day on Thursday in a strong show of Moscow’s support for its ally amid a dispute over migration at the Polish border. The Belarusian Defense Ministry said two Russian Tu-160 strategic bombers practiced bombing runs at the Ruzany firing range, located in Belarus about 37 miles east of the border with Poland. As part of the joint training, Belarusian fighter jets simulated an intercept, the ministry said. The missions marked the second time in two days that Russia sent its nuclear-capable bombers into the skies over Belarus. A pair of Russian Tu-22M3 long-range bombers flew a similar patrol on Wednesday, and Belarusian air defense assets practiced intercepting them. The Belarusian Defense Ministry said that such Russian bomber flights will be conducted on a regular basis. The Russian military said the bombers spent over 4 …