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By Eyk Henning

FRANKFURT--Several high ranking German politicians Sunday pledged to strengthen parliament's control over the country's intelligence service following allegations that it helped the U.S. spy on European allies.

"The parliament's working group needs to be beefed up significantly," Eva Hogl from the Social Democrats, which are part of the ruling grand coalition, told the website Spiegel Online Sunday. More staff, funds and a leading official coordinating control over the secret service are necessary, she added.

Berlin-based lawmakers last week said Germany's foreign intelligence service, or BND, violated German policy by eavesdropping on European targets for years at the request of the U.S. National Security Agency, reigniting public outrage in Germany over American espionage.

Thomas Strobl of the Christian Democrats, Germany's largest party, told weekly Welt am Sonntag that a BND supervisor should be installed in the parliament and be given the right to obtain any information from the intelligence agency. The supervisor should also have the right to inform the public about everything deemed necessary, he added.

Others suggested that new rules be drafted curbing the intelligence agency's powers. "We need clear rules what the BND is allowed to do" and what's forbidden, the Green Party's Konstantin von Notz told Spiegel Online. He also blamed the chancellery for having dragged its feet on the BND-NSA scandal and pledged that Chancellor Angela Merkel should attend a hearing in the committee of the parliament.

The accusations stem from government documents obtained by a parliamentary committee established to investigate the U.S. National Security Agency's surveillance activities in Germany after details of its programs were leaked by former NSA contractor Edward Snowden. German intelligence authorities used a Bavarian eavesdropping station to monitor thousands of phone numbers and Internet addresses at the NSA's behest.

The government of Ms. Merkel acknowledged that it had identified "technical and organizational shortcomings" at the BND, but has refrained from providing the parliamentary committee with details on whom the intelligence agency was monitoring.

A spokeswoman for the German government declined to comment when contacted by Dow Jones Newswires.

Write to Eyk Henning at eyk.henning@wsj.com