TOKYO (Reuters) – Japan's biggest opposition parties Sunday called on Foreign Minister Seiji Maehara to resign for accepting donations from a foreign national, piling more pressure on the embattled government of Prime Minister Naoto Kan.

Maehara, a security hawk who is often cited as a possible successor to the unpopular Kan, has said he would not quit, but added that it was up to the prime minister to decide his fate.
Maehara's resignation would be a blow to Kan and his ruling Democratic Party (DPJ) as the prime minister fights to keep his own job and avoid calling a snap election while trying to enact budget bills in a divided parliament.
""A foreign minister is at the forefront of negotiations with foreign countries. If a person in that post has taken donations from foreign nationals, resignation is unavoidable,"" Yosuke Takagi, acting secretary-general of the New Komeito party, said in a televised debate.
New Komeito is the second-largest opposition behind the Liberal Democratic Party (LDP).
Hirofumi Nakasone, head of the LDP's upper house caucus, joined Takagi by saying at another TV debate program that Maehara should ""take responsibility"" for the problematic donations.
Maehara admitted Friday that he had accepted donations from a Korean resident of Japan, but said he had done so unknowingly. Taking political donations from foreign nationals is illegal if done intentionally.