The US Federal Reserve Chairman Ben Bernanke told Congress Thursday that achieving a sustainable budget and debt balance should be a \"top priority\" for the government. Bernanke also said the US economy has strengthened but still remains vulnerable to the turmoil in the eurozone, and that if things turn worse the Fed would \"take every available step to protect the US financial system and the economy.\" Bernanke warned in testimony to the budget committee of the House of Representatives that the US fiscal trajectory remains troublesome, in both the medium and long terms. Even after sharp budget cutting by the Obama administration, based on current US taxation and spending policies, the budget gap and the ratio of country\'s debt to the size of the economy will rise rapidly. \"This dynamic is clearly unsustainable,\" Bernanke said. \"To achieve economic and financial stability, US fiscal policy must be placed on a sustainable path that ensures that debt relative to national income is at least stable or, preferably, declining over time. Attaining this goal should be a top priority.\"