NATO’s Secretary-General Jens Stoltenberg on Tuesday expressed concern over a Russian military buildup near its border with Ukraine. “We see Russian military build-up, we see heavy armor, we see drones and combat-ready troops,” Stoltenberg in a statement. “We call on Russia to be transparent because this is unprovoked and unexplained.” The comments were made as ministers of the alliance arrived for a two-day meeting in Riga, Latvia, on Nov. 30 to discuss Russia’s military buildup close to Ukraine’s border, among other issues. Ukrainian and Western officials expressed worry this month that a military buildup could signal plans by Moscow to invade its ex-Soviet neighbor. Moscow has repeatedly insisted it has no such intention and has accused Ukraine and its Western backers of making the claims to cover up their own allegedly aggressive designs. Stoltenberg said that Ukraine is a “highly valued partner” of NATO and there are different options on the table …