Germany's backing of a strict set of Europewide laws and rules revived a push by proponents of tighter regulation in Brussels on Monday.

Chancellor Angela Merkel of Germany has thrown her influence behind a European effort to protect the data of Internet users after disclosures about digital surveillance by the United States put her under intensifying political pressure heading into her re-election campaign.

Specifically citing Facebook and Google as examples of companies that would be affected by the proposal, Ms. Merkel called for the European Union to adopt legislation that would require Internet companies to disclose what information about users they store and to whom they provide it.

There is little likelihood of any concrete action by the European Union before the German elections in September, and big Internet companies are already mounting aggressive lobbying campaigns to stop or dilute any tighter privacy rules. But Germany's support for a strict set of Europewide laws and rules revived a push by proponents of tighter regulation in Brussels on Monday.

In a statement Monday, Viviane Reding, the Union's justice commissioner, who originally proposed new rules overhauling and updating the bloc's privacy standards in early 2012, praised "this commitment of Chancellor Merkel" to strengthen and uniform data protection rules in the European Union.

Ms. Merkel's statement, in a television interview Sunday night, was among the clearest expressions of anger in Germany and throughout Europe over the disclosures about the National Security Agency's activities disclosed by Edward J. Snowden, the former N.S.A. contractor who leaked classified documents.

But it also highlighted the growing strain the episode has placed on Ms. Merkel, who polls suggest remains in a strong position before the September elections but who has found herself under increasing attack from opposition parties who see the matter as an opportunity to undercut her popularity.

While the memories of the attacks of Sept. 11, 2001, define U.S. public concern for security, the history of government surveillance first under the Nazis and later by the Communist government of East Germany has translated into a heightened concern among Germans for citizens' rights to privacy.

Opposition parties have accused Ms. Merkel's government of being too deferential to the United States over the issue and of allowing German intelligence agencies to be complicit in the U.S. programs.

Peer Steinbruck, the chancellor's main rival in the election, said in an interview published Sunday that Ms. Merkel had broken her oath of office by failing in her duties to protect the German people.

"As chancellor, Ms. Merkel swore to prevent harm to the German people," he told the newspaper Bild am Sonntag, stressing that included the right to protection of their personal data.

Until now Germany has been slow to back an aggressive Europewide privacy initiative because its national laws are among the tightest in the Union. But Ms. Merkel said she now believed that only a broader pact could be effective.

"That has to be part of such a data privacy agreement, because we have great regulation for Germany, but if Facebook is registered in Ireland, then it falls under Irish jurisdiction, consequently we need a common European agreement," the chancellor said.

Facebook, along with Google, has come head to head with German sensibilities over the speed and breadth of the dissemination of private information in the age of social media and Internet shopping.

Rights groups in Germany and Austria, which has similarly strict rules guarding private information, have taken on the Silicon Valley giants over Facebook's default settings on sharing personal data and Google's scooping up of private information while mapping out German cities for its Street View service. …