The European Central Bank says it is ready to buy the government bonds of the continent's debt-ridden countries, a move that could ease the rising borrowing costs of financially troubled Spain and Italy. Bank President Mario Draghi did not disclose the size of the bond purchases, but today said, it would be sizeable enough for the bank to reach its objective of stabilizing borrowing costs in the 17-nation euro currency union. He said details of the bond purchases would be worked out in the coming weeks. Both the Madrid and Rome governments have struggled to contain their borrowing costs – with the interest rates on Spain's debt topping the level at which Greece, Ireland and Portugal all were forced to secure international bailouts. Some analysts have said the economic problems in the eurozone imperil the existence of the currency. But after bank policy makers met in Frankfurt, Draghi declared, the euro is irreversible.