MOSCOW (AP) — Russia's Defense Ministry said Thursday that the United States appeared to be running a clandestine biological weapons lab in the country of Georgia, allegedly flouting international conventions and posing a direct security threat to Russia — allegations the Pentagon angrily rejected.

The exceptional accusations from Moscow came the same day U.S., British and Dutch officials accused Russian military intelligence of being behind multiple cyberattacks.

Maj. Gen. Igor Kirillov, the head of the Russian military's radiation, chemical and biological protection troops, alleged at a brie...