Explained: Why is Russia massing troops in Donbas region of eastern Ukraine?

Last week, Ukrainian commander-in-chief Ruslan Khomchak accused Russia of pursuing an “aggressive policy” towards Kyiv by amassing troops near the contested Donbas region.

Ukrainian President Volodymyr Zelenskiy is set to hold talks on Saturday with his Turkish counterpart Recep Tayyip Erdogan amid rising tension with Russia over the conflict in Ukraine's eastern Donbas region. Last week, Ukrainian commander-in-chief Ruslan Khomchak accused Moscow of pursuing an “aggressive policy” towards Kyiv by amassing troops near the contested region.

Ukrainian President Volodymyr Zelenskiy visits the war-hit Donbas region amid tensions over Russia's troops' movement. (AP)

The continued military build-up in the area around eastern Ukraine has triggered a strong response from the West as the United States has warned of “consequences”. White House press secretary Jen Psaki said at a daily briefing that the US is in close consultation with its allies in the region over Russia’s troop movements. “Of the actions that have already been taken, that we’ve had an ongoing review about we’ve been clear, There will be consequences, some unseen and some seen. We will hope to have more about those soon,” Psaki said on Friday.

During a phone call with Russian President Vladimir Putin, German Chancellor Angela Merkel demanded a reduction in troops at the Ukrainian border. "One subject of their conversation was, among others, the increased Russian military presence near eastern Ukraine. The chancellor called for a reduction of these troop reinforcements to de-escalate tensions," the German government said in a statement.

However, Moscow accused Kyiv of provocative actions which “has recently purposefully escalated the situation on the line of contact”. Kremlin said in a statement that Putin stressed the need for strict implementation of previously reached agreements to “legally formalise the special status of Donbas”.

Ukraine, a country geographically divided between Europe and Russia, has pro-Russia and pro-West people. The fourth Ukrainian president, Viktor Yanukovych, was pro-Russia and backed away from EU Association Agreement in November 2013 to prevent the country from turning to the West. Yanukovych’s U-turn over signing the agreement triggered protests and he had to flee to Russia.

Ukraine's President Volodymyr Zelenskiy visits positions of armed forces near the frontline with Russian-backed separatists during his working trip in Donbass region. (via Reuters)

The tensions later spread to Crimea and the territory was annexed by Russia following a controversial referendum, which Crimean Tatars, an East European Turkic ethnic group, and Ukrainians had objected to. The long-running conflict has claimed more than 13,000 lives since 2014. Pro-Russian separatists also claim control over the Donbas region, which includes Donetsk and Luhansk provinces.

Minsk Agreements were signed between the pro-Russian separatists and the Kyiv administration to stop the armed conflict. The agreements called for a ceasefire in the region as well as prisoner exchange while allowing the Ukrainian government to make a constitutional amendment that would provide for special status to Donbas. But the implementation of those agreements has been hampered by multiple ceasefire violations for which the two sides have traded blames.

Earlier this week, Zelensky urged Nato, an intergovernmental military alliance between Western powers, to speed up his country’s membership. In a phone call with NATO chief Jens Stoltenberg, the Ukrainian president said that it was the only way to end fighting with pro-Russia separatists and end the war in Donbas. Russia sees Ukraine’s entry into Nato as a threat and fears have been mounting of a major escalation in the conflict areas.