Up to 20 people are still missing after devastating floods killed at least a dozen people in the Georgian capital Tbilisi, with escaped zoo animals still on the loose Monday.

The government of the ex-Soviet republic said the death toll after the Vere river burst its banks on Sunday following hours of torrential rain stood at 12 on Monday morning. 

Lions, tigers and even a hippopotamus escaped from a zoo in the Georgian capital Tbilisi Sunday, adding to chaos caused by severe flooding that killed at least 12 people, officials said.

Police and soldiers were hunting down the animals, recapturing some and shooting others dead, while rescuers airlifted scores of people trapped by the floods.

Over 30,000 opposition supporters rallied on Saturday in the Georgian capital Tbilisi against the government's Russia policy and the Kremlin's backing of separatists in the breakaway Abkhazia and South Ossetia regions.

Carrying Georgian and Ukrainian flags and placards that read "Stop Putin!", the protesters gathered on the city's main thoroughfare, following the call of the former president Mikheil Saakashvili's United National Movement party (UNM).

Georgia on Tuesday lashed out at arch-foe Russia over the construction of a new barrier along its disputed frontline with the breakaway region of South Ossetia.

"The foreign ministry of Georgia expresses its deep concern over the installation of wire fences by the Russian occupation forces across the Tskhinvali region's occupation line," the ministry said in a statement.

Fifty-six people including six children have been hospitalized in Georgia with chlorine poisoning after a storage tank leaked overnight in a suburb of the capital Tbilisi, officials said Wednesday.

"At around midnight in the Lilo district of Tbilisi there was a leak from a chlorine container. As a result, 56 people were poisoned and taken to hospital," interior ministry spokesman Zurab Gvenetadze told Agence France Presse.

Israel's Ambassador to the U.N., Ron Prosor, has warned the Security Council that Hizbullah’s alleged powerbase in western Africa is growing, the Israeli Ynetnews website reported Wednesday.

"Israel is particularly concerned over Hizbullah's use of the area as a base of terror operations,” the site quoted Prosor as saying. “Criminal initiatives bolster Hizbullah's efforts to create sleeper-cells in the area.”

U.S. Homeland Security Secretary Janet Napolitano has said the U.S. is closely monitoring the activities of Hizbullah after a failed bomb plot in Bangkok and attacks on Israeli embassy staff in India and Georgia.

Napolitano told lawmakers Wednesday that the Homeland Security Department has contacted Jewish organizations around the country and is working with the FBI and other law enforcement and intelligence agencies.

Indian investigators were searching Tuesday for the motorcycle assailant who attached a bomb to an Israeli diplomatic car in the heart of New Delhi, an attack the Jewish state blamed on Iran or its proxies, including Hizbullah.

Home Minister Palaniappan Chidambaram told reporters investigators were working on the assumption it was a terror attack carried out by a "very well-trained person."