The Russian government has said the capital, Moscow, came under attack from three Ukrainian drones on Sunday. 

The Russian state-owned TASS news agency said one person — a security guard — was injured. The alleged attack caused the temporary suspension of flights at Moscow's Vnukovo International Airport.

If confirmed, it would be the fourth such attempt at a strike on the capital region this month and the third this week. Moscow is about 500 kilometers (310 miles) from the Ukrainian border.

The incident is likely to fuel fears in Russia that its invasion of Ukraine, now in its 18th month, could increasingly make its own territory the target of retaliatory attacks. 

What do we know so far?

According to TASS, Russia's Defense Ministry said one of the drones was destroyed in the air over the Odintsovo district in the Moscow region and two others crashed in the capital city itself, brought down by "radio-electronic equipment."

Photos from the crash site showed a damaged skyscraper facade. Moscow Mayor Sergei Sobyanin said two buildings in the Moscow City district in the west of the capital were "insignificantly damaged."

 Operations at the Vnukovo airport, one of four around the Russian capital, appeared to have returned to normal within less than an hour of the incidents.

There was no immediate comment from Ukrainian officials. Kyiv rarely, if ever, takes responsibility for attacks on Russian soil.

tj/wd (Reuters, AP)