TOKYO >> Japan’s foreign minister suddenly quit for having accepted a political donation from a foreigner — a violation of Japanese law — dealing another blow to the embattled administration of Prime Minister Naoto Kan.

Seiji Maehara, 48, was foreign minister for just six months until Sunday, and was viewed as a leading candidate to succeed Kan. The government said Monday that Chief Cabinet Secretary Yukio Edano will temporarily double as foreign minister.

Maehara acknowledged receiving a total of 250,000 yen ($3,000) over the past several years from a 72-year-old Korean woman who has lived most of her life in Japan. He said they had been friends since his childhood.

Japanese law makes it very hard for foreigners to become citizens, even if their families have lived in the country for generations. The foreign residents include hundreds of thousands of ethnic Koreans, many descended from laborers brought forcibly to Japan during World War II.

Japan’s political funding law prohibits lawmakers from accepting donations from any foreigners, even those born in Japan.

Maehara’s resignation at a televised news conference Sunday night furthers the high turnover that has plagued government officials in recent years and is likely to further erode public confidence in Kan — the country’s fifth leader in four years — whose public approval rating has fallen below 20 percent.

Japanese have grown disillusioned over the government’s inability to move ahead in tackling serious problems, from a lackluster economy and bulging national debt to an aging, shrinking population.

"I apologize to the people that I ended up resigning after just six months on the job, and for causing distrust due to a politics-and-money problem despite my pledge to seek clean politics," Maehara said, bowing. "It’s truly regrettable that I caused such a problem because of my own mistake."

His admission undermines Kan’s pledge to root out "money politics" after a veteran power broker in the ruling Democratic Party of Japan, Ichiro Ozawa, was ensnared in a political funding scandal. Ozawa says he is innocent, but the party has recommended revoking his membership.

Opposition parties, which have worked hard to obstruct the Democrats’ attempts to pass the budget and move ahead on other legislation, will likely be emboldened by Maehara’s resignation.

Atsuo Ito, an independent political analyst, said the resignation was inevitable to save Kan’s government from further trouble.

"If he had stayed on, he would have come under heavy fire in parliament," he said in an interview with Fuji TV.