All four of Moscow's airports including another about 100 miles southwest of the Russian capital were temporarily shut down for undisclosed security concerns, authorities said.

All four Moscow airports reopened after a brief time, including an additional airport in Kaluga which reopened later this afternoon - as of yet no reason has been given

Russia's aviation authority announced the temporary closure of all Moscow airports and the Kaluga airport. The statement did not specify reasons but emphasized that crews and controllers are ensuring flight safety.