Christian Democratic Union (CDU) Chairwoman and German Chancellor Angela Merkel applauds on Monday in Leipzig, eastern Germany, during the opening of the CDU congress. Merkel seeks at the two-day party gathering to rally her party amid mounting ire at Germany having to stump up the lion's share in fighting Europe's debt crisis. [Johannes Eisele / Agence France-Presse]

BERLIN - German Chancellor Angela Merkel called on Monday for a stronger "political union" in Europe to overcome the bloc's debt crisis, which she described as "maybe Europe's most difficult hours since World War II".

As leaders move ahead in uncharted territory, a breakthrough will be achieved not by "less Europe, but more", she told members of her conservative party gathered for their annual convention in the eastern German city of Leipzig.

The European Union's treaties must be overhauled to create a tighter political union, including measures to force countries in violation of fiscal discipline rules to face tough and automatic sanctions, even possibly hauling them to the European Court of Justice, Merkel said.

"We must develop the European Union's structure further. That does not mean less Europe, but more. That means creating a Europe that ensures that the euro has a future," she said in unusually passionate comments. "Our generation's duty now is to finalize the economic and currency union to form, step by step, a political union."

Structural changes to the EU as championed by Merkel would require the bloc's treaties to be amended which is a lengthy procedure that has in the past sometimes taken years, with all of the bloc's 27 governments, parliaments or, in some cases, voters in a referendum having to approve the changes.

The leader of Europe's biggest economy said the crisis led people across the continent to realize that the problems of any state within the 17-nation eurozone today are also the problems of all other members.

"Our responsibility no longer stops at our countries' borders," Merkel insisted.

Internationally, she has often been criticized for moving too slowly and reluctantly in tackling Europe's debt crisis. Within her Christian Democratic Union (CDU), however, the opposite appears to be true as she is facing rising criticism in the wake of costly bailouts of Greece and other debt-swamped member nations.

The chancellor therefore stressed that Germany depends on the EU as its main trading partner, and insisted that the country can only wield global influence as a leading European nation. Germany, a country of 82 million, is the world's fourth-largest economy.

"Alone, with just more than 1 percent of the world's population, we won't achieve much," she said.

"The euro is more than a currency. It is the symbol of Europe's unification. It is the symbol for half a century of freedom and peace," Merkel said. "Now we have to make sure that Europe will emerge strengthened from this crisis."

Merkel, who does not stand for re-election as the CDU's chairwoman until next year, also defended a series of political decisions that have been criticized by many party members, including abandoning conscription and speeding up the country's exit from nuclear power.

Associated Press