Russia's aviation watchdog said on Thursday all four Moscow airports had resumed work after the lifting of temporary restrictions that were introduced to ensure the safety of civil aircraft flights. "Aircraft crews,

"To ensure the safety of civil aircraft flights, temporary restrictions have been introduced on the operation of Sheremetyevo, Domodedovo, Vnukovo, Zhukovsky and Kaluga airports," Rosaviatsiya said on Dec.

Russia's aviation authority announced on Thursday the temporary closure of five airports, including all four Moscow airports and one in Kaluga, located 160km southwest of the capital. The aviation watchdog Rosaviatsia did not provide a reason for the closures.

Russian Deputy Foreign Minister Sergei Ryabkov said Moscow is considering taking steps to resume nuclear tests. He made the warning while cautioning President-elect Donald Trump against resuming nuclear testing next year in an interview with the Russian newspaper Kommersant.

Russia's point man for arms control cautioned Donald Trump's incoming administration against resuming nuclear testing, saying Moscow would keep its own options open.

Moscow has warned Donald Trump against resuming the testing of nuclear weapons when he takes office, saying it would “not rule anything out” in response to US aggression.

“While other countries of the world are celebrating Christmas, Ukrainians are continuing to suffer from endless Russian attacks,” Ukraine’s human rights ombudsman Dmytro Lubinets wrote on Telegram.

Andrii Yusov of Ukraine's Defense Intelligence said that Kyiv is increasing the range of its unmanned aerial vehicles.

Russia’s drone strikes on Ukraine have increased sixfold in four months. The offensive is being fueled by a facility in Russia’s southern Tatarstan region, which is ramping up production with the help of a low-skilled workforce of Russian students.