Social media posts on Friday said air-defense systems have been installed in several spots in Moscow, including atop the Russian Defense Ministry headquarters.
Russian officials have not commented on the reports of weaponry resembling a Pantsir-S1 mobile anti-aircraft system spotted on the roofs of a building in central Moscow about 2 kilometers (1.2 miles) east of the Kremlin and of the Defense Ministry, which looms along the Moscow River across from Gorky Park.
Reports earlier in the week said S-400 mobile surface-to-air missile units were seen near the sprawling Losiny Ostrov forest park on Moscow’s northern border and at an agricultural institute in the capital.
Since Russia sent troops into Ukraine nearly 11 months ago, it has been hit with several drone strikes or attempted strikes deep inside its territory. Authorities said a Dec. 5 drone strike killed three people at a military airfield some 600 kilometers (370 miles) from the Ukrainian border.
Explosive drones also struck the Russian Black Sea Fleet headquarters in Russia-annexed Crimea.
While the United States and other NATO members have provided billions of dollars’ worth of military aid to Ukraine, U.S. President Joe Biden has said that Washington would not send weapons that could be used for attacks inside of Russia.
Kremlin spokesman, Dmitry Peskov, nevertheless raised the prospect on Thursday of such weapons being supplied in the future, saying it would “bring the conflict to a whole new level.”