Russia’s President Vladimir Putin on Friday called on pro-Russian separatists fighting government troops in eastern Ukraine to release Ukrainian soldiers who have been surrounded by the rebels.

Putin’s statement came several hours after Ukraine accused Russia of entering its territory with tanks, artillery and troops, and Western powers lashed out at Moscow for lying about its role and dangerously escalating the conflict.

NATO said at least 1,000 Russian troops are in Ukraine and later released what it said were satellite photos of Russian self-propelled artillery units moving last week

“I’m calling on insurgents to open a humanitarian corridor for Ukrainian troops who were surrounded in order to avoid senseless deaths,” Putin said in the statement published on the Kremlin’s website in the early hours on Friday. He did not address the claims about Russia’s military presence in Ukraine.

Russian President Vladimir Putin in Moscow on June 22, 2014. (photo credit: AP Photo/Alexander Zemlianichenko)

Russian President Vladimir Putin in Moscow on June 22, 2014. (photo credit: AP Photo/Alexander Zemlianichenko)

Putin’s statement could be referring to Ukrainian troops who have been trapped outside the strategic town of Ilovaysk, east of Donetsk, for nearly a week now. Protesters rallied outside the Ukrainian General Staff on Thursday, demanding reinforcements and heavy weaponry for the troops outside Ilovaysk, most of whom are volunteers.

Copyright 2014 The Associated Press.