MOSCOW, Feb 28 (Aljazeera) - Russian President Vladimir Putin has ordered officials to tighten control of the border with Ukraine after a spate of drone attacks that Russian authorities blamed on Kyiv delivered a new challenge to Moscow a year after its full-scale invasion of its neighbour.

One drone crashed on Tuesday just 100km (60 miles) southeast of Moscow in an alarming development for Russian defences.

While Putin didn’t refer to any specific attacks in a speech in the Russian capital, he stepped up border controls hours after drone attacks targeted several areas in southern and western Russia and authorities closed the airspace over St Petersburg in response to what some reports said was a drone.

Also on Tuesday, several Russian television stations aired a missile attack warning that officials blamed on hacking.

The drone attacks caused no casualties but provoked a security stir after the war in Ukraine marked its first anniversary last week.

Ukrainian officials did not immediately claim responsibility for the attacks, but they similarly avoided directly acknowledging responsibility for previous strikes and sabotage while emphasising Kyiv’s right to hit any target in Russia after Moscow launched its full-scale invasion of Ukraine.