An alarming photo has offered grim insight into growing tensions between Ukraine and Russia as both nations accuse the other of violating a ceasefire agreement.
Images showing tanks rolling into eastern Ukrainian cities of Donetsk and Luhansk in Donbass have been circulating online in recent days as the country accuses Moscow of ramping up provocations in border regions.
Donetsk and Luhansk are held by Russian-backed separatists — rebel Ukrainians who have formed a militia under the command of pro-Russian commander, Igor Girkin.
Ukraine capital Kiev has been locked in a conflict with the Russian-backed separatists since 2014, with Russian troop movement detected this week in annexed Crimea and on the border, near territories controlled by the separatists.
Russia warned on Thursday that a serious escalation in the conflict in Donbass could "destroy" Ukraine as NATO voiced concern over what it said was a big Russian military build-up near eastern Ukraine.
Unverified social media footage has suggested Russia has been moving large quantities of tanks, armoured personnel carriers and other equipment to regions that border Ukraine as well as to Crimea, which Moscow annexed from Ukraine in 2014.
Ukrainian President Volodymyr Zelensky's ministers on Thursday (local time) discussed the escalating security situation with Western allies including US Secretary of Defence Lloyd Austin.
"Muscle-flexing in the form of military exercises and possible provocations along the border are traditional Russian games," Zelensky said in a statement.
He accused Moscow of seeking to create "a threatening atmosphere" as Kiev hopes to resume the ceasefire, which was brokered last year.
The US State Department said it was "absolutely concerned by recent escalations of Russian aggressive and provocative actions in eastern Ukraine".
"What we would object to are aggressive actions that have an intent of intimidating, or threatening, our partner Ukraine," State Department spokesman Ned Price told reporters.
Some observers say the reported Russian troop buildup is a test for the administration of US President Joe Biden, who caused an uproar in Moscow last month by calling his Russian counterpart Vladimir Putin a "killer".
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This week, Moscow and Kiev blamed each other for a rise in violence between government forces and Kremlin-backed separatists in eastern Ukraine, which has undermined the ceasefire.
Zelensky said 20 Ukrainian servicemen had been killed and 57 wounded since the start of the year.
Separately, the military announced that a Ukrainian soldier was wounded in an attack it blamed on separatists.
'Ready for an offensive'
On Thursday, Austin, the US Secretary of Defence, called his Ukrainian counterpart Andriy Taran, Ukraine's defence ministry said.
Austin said during the call that Washington would "not leave Ukraine alone in the event of escalating Russian aggression", the ministry said.
Ukrainian Foreign Minister Dmytro Kuleba discussed the "aggravation by the Russian Federation of the security situation" on the frontline with his Canadian counterpart Marc Garneau.
Ukraine's military intelligence accused Russia of preparing to "expand its military presence" in the separatist-controlled eastern regions of Donetsk and Lugansk.
In a statement, the intelligence service said it "does not rule out" an attempt by Russian forces to move "deep into Ukrainian territory".
A high-ranking Ukrainian government official, speaking on condition of anonymity, claimed that the Russian army was practising "military coordination" with separatists.
"From mid-April their combat units will be ready for an offensive," the official told AFP.
West should not 'worry'
Moscow has repeatedly denied sending troops and arms to buttress the separatists and Putin's spokesman stressed on Thursday that Moscow is at liberty to move troops across its territory.
"The Russian Federation moves its armed forces within its territory at its discretion," spokesman Dmitry Peskov told reporters, but he did not directly confirm a troop build-up on the Ukrainian border.
He added that "it should not worry anyone and does not pose a threat to anyone".
The war in eastern Ukraine broke out in 2014 when Russia annexed the Crimean peninsula following a bloody uprising that ousted Ukraine's Kremlin-friendly president Viktor Yanukovych.
On Wednesday, the Pentagon said US forces in Europe had raised their alert status following the "recent escalations of Russian aggression in eastern Ukraine".
Mark Milley, chairman the US Joint Chiefs of Staff, also spoke with his Russian and Ukrainian counterparts, Valery Gerasimov and Ruslan Khomchak.
Khomchak said this week that 28,000 separatist fighters and "more than 2,000 Russian military instructors and advisers" are currently stationed in eastern Ukraine.
On Thursday, the deputy head of Zelensky's office, Roman Mashovets, called for joint drills with NATO forces to "help stabilise the security situation".
Zelensky was elected in 2019 promising to end the years-long conflict, but critics say a shaky ceasefire was his only tangible achievement.
The fighting has claimed more than 13,000 lives since 2014, according to the United Nations.
With AFP and Reuters
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