Japanese Prime Minister Shinzo Abe led his scandal-stained ruling coalition to an unexpectedly severe defeat in parliamentary elections Sunday, a stunning reversal of fortune for a party that has controlled Japan virtually uninterrupted since 1955. Despite the humiliating setback, Abe vowed to stay in office. Official election results released Monday showed Abe's Liberal Democratic Party and its junior coalition partner, New Komeito, losing their majority in the 242-seat upper house. The two retained 103 seats, a 30-seat loss well short of the 122 needed to control the chamber. The leading opposition Democratic Party of Japan made huge gains in the race for the 121 contested seats. It now has 112 seats, up from 81. It would be unusual for a prime minister to step down after an upper-house defeat. But calls for Abe's resignation from within his own party are expected to grow. Looking grim and chastened, the prime minister called the results "severe" but dismissed questions about whether he should resign. He was expected to meet with New Komeito leader Akihiro Ota later Monday to confirm their partnership. "I must push ahead with reforms and continue to fulfill my responsibilities as prime minister," Abe said at his party's headquarters. "The responsibility for this utter defeat rests with me." LDP's loss in the less-powerful upper house would not immediately threaten its political grip because it controls the lower chamber, which chooses the prime minister. But the defeat could make it more difficult for the LDP to pass bills, while enlivening policy debates. Abe dismissed opposition calls for an election for the lower house to test his mandate. "The nation has spoken very clearly," Democratic Party of Japan leader Naoto Kan told reporters. "Naturally, our sights are on the lower house and our final goal is a change in government." Japan's largest newspaper, Yomiuri, on Monday called the results, "a major blow to the Abe government," and added: "The results would largely affect Prime Minister Abe's political management and parliamentary operation." Asahi, another major paper, declared "The prime minister should face the results seriously and step down." Abe's top lieutenant, party No. 2 Hidenao Nakagawa, said late Sunday he would step down to take responsibility for the party's setback. "If the results are as projected, we have suffered an utter defeat," Nakagawa said hours after the polls closed. Abe also said he plans to reshuffle his Cabinet after a special session of Parliament, which has not yet been scheduled. "Voters said we must reflect on our shortcomings and refresh the lineup," Abe said. "I plan to reshuffle the Cabinet and top party posts at an appropriate time." Abe, 52, took office in September as Japan's youngest-ever prime minister, promising to build a "beautiful Japan," and won points for mending strained diplomatic ties with South Korea and China. But his honeymoon was short-lived. In the first in a series of scandals, Administrative Reform Minister Genichiro Sata stepped down in December over charges of misusing of political funds. In May, Abe's agriculture minister killed himself amid allegations he also misused public money. The new agriculture minister became embroiled in another funds scandal. The government was severely criticized again last month when Defense Minister Fumio Kyuma suggested the 1945 U.S. nuclear bombings of Japan were justified. Public outcry led to Kyuma's speedy departure. Perhaps the final straw for voters was Abe's brushing off warnings by the opposition late last year that pension records had been lost. That inaction came back to haunt him in the spring, when the full scope of the records losses emerged. Some 50 million claims had been wiped out. "I don't like Abe or the LDP. I don't get the feeling things have gotten better," said Masayoshi Miyazaki, 58, a Tokyo retiree, after polls closed. Party officials said last week they would keep Abe no matter what happens, and resigning in the face of a heavy election defeat is rare, but not unprecedented. In 1998, then-Prime Minster Ryutaro Hashimoto was forced to step down after the Liberal Democratic Party won just 44 seats out of 121. Sousuke Uno lost his job as prime minister after winning only 36 seats in 1989. Abe himself resigned as secretary-general of the party in 2004, when the Liberal Democrats won 49 seats, two short of their goal. Some unconventional candidates from outside the two major parties also fared badly Sunday. Alberto Fujimori, the former Peruvian authoritarian leader; Yuko Tojo, the granddaughter of the executed wartime general who ordered the attack on Pearl Harbor; and the popular inventor Dr. Nakamats were all headed for defeat, according to projections.