People who dealt with removing the consequences of the 1986 Chernobyl nuclear disaster in Ukraine, or 'liquidators,' compared the two accidents.

"Intensive activity started in Chernobyl on the first day [since the accident], but in Japan, it's very slow. In my opinion, they lost much time and still can't control what is happening," Col. Gen. Nikolai Antoshkin, one of the Chernobyl liquidators, told RIA Novosti on Friday.

Another liquidator, Nikolai Tarakanov, said Fukushima reactors dating back to 1974 cause his concern as they are "too old."

The confirmed death toll from the March 11 earthquake and tsunami stands at more than 10,000, according to police, and over 17,440 are listed as missing.

Operations have continued to restart the cooling systems at Fukushima's six reactors to try to avoid a major radioactive release.

The Japanese government on Friday asked people still living within 30 km (19 miles) of the damaged plant to leave due to shortages of food and other essentials.

Food, water and fuel in prefectures around Fukushima are in short supply over contamination fears, while countries including the United States, Russia and Australian have banned the imports of food products from Fukushima, Ibaraki, Tochigi and Gunma prefectures.