TOKYO -- Fresh off a spectacular election win, Japan's opposition on Monday demanded that Prime Minister Shinzo Abe resign, opposed his support of U.S. foreign policy and promised to gain leadership of the world's second-largest economy.
A defiant Abe clung to his job despite Sunday's humiliating loss in parliamentary elections, warning of a political vacuum if he were to quit and instead announcing he would make changes soon in his scandal-riddled Cabinet.
"I cannot run away now," Abe told reporters as he dismissed mounting public pressure to step down for losing the majority in parliament's upper house. "We cannot afford a political vacuum."
"Japan is in the midst of reforms that must be carried forward," he said.
However, the ruling party's No. 2 man, Secretary-General Hidenao Nakagawa, did announce that he would resign.
On Sunday, voters stripped the ruling Liberal Democratic Party and its junior coalition partner of their majority in parliament's 242-seat body upper chamber. The main opposition Democratic Party of Japan became the No. 1 party in the upper house -- heralding an era of political deadlock with the Liberal Democratic Party, which remains in control of the lower house.
The Democratic Party of Japan was quick to assert its newfound clout, ridiculing Abe's decision to stay on as prime minister and questioning some of his most basic policies.
"It's clear that the nation has given Mr. Abe a clear 'no.' How he can ignore that is absolutely baffling," acting party chief Naoto Kan said in a televised debate. He spoke on behalf of party leader Ichiro Ozawa, who was recovering from a cold.
"The public has given us a mandate," Kan said. "We will see in lower house elections which party they want in power."
Another opposition party leader, Yukio Hatoyama, said the Democratic Party of Japan would oppose extending Japan's naval mission to support U.S.-led operations in Afghanistan. The Japanese navy has provided fuel for coalition warships in the Indian Ocean since 2001; the current mission expires in November.
"We have always been fundamentally opposed to extending," Hatoyama said. "The upper house elections have shown the country agrees, and so we will be expected to keep that line."
The Indian Ocean mission has been part of Tokyo's recent attempts to raise its international profile. Japan also sent non-combat troops to help rebuild southern Iraq.
The opposition party has criticized both operations, saying Japan's international efforts should be channeled through the United Nations, not the United States. Some within the party also say the missions violate the nation's pacifist constitution, which prohibits the use of force to solve international disputes.
Democratic Party of Japan officials also have criticized Abe over scandals in his Cabinet, including the alleged misuse of funds that has resulted in the departure of two ministers and is threatening a third. Kan also demanded that Abe address a widening pension records debacle that resulted in the loss of 50 million claims.
The election was a dramatic reversal of the support Abe enjoyed when he took over from the popular Junichiro Koizumi less than a year ago. The opposition appeared closer than ever toward ending the Liberal Democrats' virtually uninterrupted grip on power since its founding in 1955.
Under Ozawa, the Democratic Party of Japan has made gains on a reform platform. Like the ruling party, Ozawa advocates an expanded role in international peacekeeping for Japan's military, but has criticized what he says is Abe's blind support of U.S. foreign policy.
Still, the opposition would have to prove its mandate in elections in parliament's lower house, which Abe is not required to call for another two years. On Monday, Abe rebuffed suggestions that he should call snap elections for the lower chamber.
While there is no clear front-runner to replace Abe as premier, the hawkish Foreign Minister Taro Aso is often cited as a possible contender.
Analysts said the opposition party's prospects were good.
"The Democrats are on their way up and have nothing to lose," said Tsuneo Watanabe, a Tokyo-based political analyst with the Center for Strategic and International Studies.
"Abe may stay on, but the party is in disarray and the damage may be irreversible," he said. "A change in leadership could be in the works for Japan."