While continuing to offer aid to Japan, many countries also are evacuating their citizens from the worst-hit areas of the country amid aftershocks and fears of nuclear leaks after Friday's 9.0-magnitude earthquake and ensuing tsunami.
The disaster has so far killed at least 3,676 people and left at least 7,558 others missing, Japanese public broadcaster NHK reported Wednesday.
On Wednesday, the city of Wenzhou in east China's Zhejiang Province announced the donation of 2 million yuan (307,692 dollars) to Ishinomaki, its Japanese sister city in the hard-hit Miyagi Prefecture.
The move followed Foreign Ministry spokeswoman Jiang Yu's remarks Tuesday that China would continue to provide Japan with necessary assistance in accordance with the latter's needs.
Previously, the provincial government of northeast China's Jilin Province said it would donate 100,000 dollars to the prefectural government of Miyagi while the municipal government of Changchun, capital of Jilin, pledged 500,000 yuan (about 77,000 dollars) to the municipal government of Sendai.
The Chinese government also announced its decision Wednesday to provide 20,000 tons of fuel as emergency assistance to Japan.
The amount,10,000 tons of gasoline and 10,000 tons of diesel, would be supplied to Japan in addition to the Chinese government's decision on Monday to provide 30 million yuan (about 4.6 million dollars) in emergency humanitarian aid to support disaster relief.
At the same time, South Korea is offering boric acid to Japan to help it cope with its unfolding nuclear crisis.
Seoul has sent a sample of boric acid to assess usability of the material, which can slow down nuclear reactions and help contain radiation, before sending 52.6 tons as requested by Tokyo, said the Ministry of Knowledge Economy.
The ministry added that it can well supply the requested amount of boric acid, with reserves at home currently estimated at 309 tons.
Radiation has been leaking from damaged reactors at a crippled nuclear power plant in the Fukushima Prefecture, affecting up to 190 people in the area and causing tens of thousands of residents to evacuate.
Japanese authorities have poured boric acid and seawater into the reactors in a last-ditch effort to cool the reactors following a series of explosions at the stricken plant.
Meanwhile, Vietnam's Red Cross on Wednesday affirmed the country's third donation of 10,000 U.S. dollars to Japanese victims by Vietnam's Telecoms Group and Post Trade Union, after a first of 200,000 dollars by the government, and 50,000 dollars from the Red Cross.
Cambodia and Laos have respectively contributed 100,000 dollars for the relief of the victims, while Indonesia and the Philippines are sending search and rescue teams to Japan.
Thailand, the world's largest rice exporter, has promised 15,000 tons of rice and over 6.5 million dollars' worth of assistance.
Regional organizations and countries outside Asia have also vowed to help Japan.
The Shanghai Cooperation Organization (SCO) on Wednesday extended its condolences to the Japanese government and people suffering from the catastrophe and pledged to help Japan overcome its difficulties, as well as erase future consequences brought on by the earthquake.
Meanwhile, Cuba has offered to send medical and rescue workers to Japan.
The official agency AIN said that the Cuban ambassador in Tokyo, Jose Fernandez de Cossio, said the Japanese government has acknowledged Cuba's willingness to provide rescue and medical aid.