Ukraine is a cliffhanger, the chancellor said: “It is not yet clear whether Ukraine is willing to create the conditions” to sign the association agreement with the European Union, which would open up trade and other economic benefits and make travel to Western Europe easier.

The debate over the union’s Eastern Partnership program in the German Parliament was followed by a lively discussion of the recent accusations that Germany’s most important ally, the United States, eavesdropped on millions of Germans, including the chancellor.

Ms. Merkel, displaying barely a trace of the anger that she voiced when the monitoring of her cellphone became known, seemed intent on tamping down the hard feelings that have developed over the affair. Still, she insisted that the United States had work to do to restore the confidence needed, for example, to negotiate a free trade accord with the European Union.

The spying accusations “are grave,” the chancellor said. “They must be cleared up. And, more important still: for the future, we must build new trust.”

In the debate, Frank-Walter Steinmeier, a former foreign minister and member of the Social Democrats, with whom Ms. Merkel is now negotiating a new coalition government, said there was more to the matter than merely the discovery that the United States had spied on Germany.

“People sense that this is not a one-time oversight,” Mr. Steinmeier told the Parliament. “People sense that this is about a very basic question. This is about which moral and political guidelines do we need in this modern, digital 21st century?”

Edward J. Snowden, the former National Security Agency contractor, has disclosed information about the agency’s surveillance operations to various publications — in Germany, primarily to the news weekly Der Spiegel. Several prominent politicians and intellectuals on the left have demanded that Mr. Snowden, who now has temporary asylum in Russia, be given shelter in Germany and be allowed to answer questions before a full-fledged parliamentary inquiry.

The chancellor’s conservative bloc and the Social Democrats used their combined majority on Monday to reject opposition calls for an inquiry. Still, such an inquiry could be established after Ms. Merkel is sworn in as head of a new government, which is expected to happen on Dec. 17.