AlHijjah 29, 1432, Nov 25, 2011, SPA -- The International Monetary Fund warned in a new report that market concerns over fiscal sustainability could trigger a "sudden spike" in Japanese government bond yields that could quickly render the nation's debt unsustainable as well as shake the global economy. The fund's Japan Sustainability Report, released on Wednesday, was a signal to Tokyo policy makers that the international community is already worried about fallouts from Japan's potential fiscal problems, after debt problems in some European economies evolved into a Continent-wide crisis. Japan's public liabilities amount to roughly twice annual economic output-a ratio worse than that of any other industrialized economy, including turmoil-hit Spain and Italy. The Japanese government has been slow to move amid political reluctance to lift taxes, particularly after the March 11 earthquake. "Should JGB yields rise from current levels, Japanese debt could quickly become unsustainable," the IMF said in the report. "Recent events in other advanced economies have underscored how quickly market sentiment toward sovereigns with unsustainable fiscal imbalances can shift," the fund said. Higher government bond yields "could result in a withdrawal of liquidity from global capital markets, disrupt external positions and, through contagion, put upward pressure on sovereign-bond yields elsewhere," the fund said.