At least 52 people have been killed in mudslides and flooding in a mountainous region of Soviet Georgia, Radio Moscow said Friday.

Meanwhile, a bus carrying 20 people is missing and may have been swept off a road by a torrent of mud, an editor at Georgia's official Gruzinform news agency also reported.The editor, who did not give his name, said in a telephone interview that the mudslides occurred Wednesday evening.

Radio Moscow said the hardest hit areas were in the Adzharia region of southern Georgia along the Black Sea coast.

"Plans have been worked out to evacuate about 3,000 persons," the official radio said, adding, "Sunday has been declared an official day of mourning."

Tass, the official news agency, said in the first reports on the disaster Thursday that landslides, avalanches and floods destroyed or heavily damaged more than 500 houses.