US President Barack Obama is looking to ban gathering intelligence on allies, a senior US official said on Tuesday, amid widespread outrage over Washington tracking millions of phones and e-mail accounts across Europe, including the mobile phone of German Chancellor Angela Merkel.
The official said the US has made some individual changes in spying practices but so far there was little change in the general policy of snooping on allies.
"We recognize there needs to be additional constraints on how we gather and use intelligence," White House spokesperson Jay Carney said at a media briefing on Monday.
"There are a number of efforts underway that are designed to increase transparency, to work with Congress to look at reform to the Patriot Act (and) to look at ways we can increase oversight."
Immediately after reports in the German media surfaced last week of US' phone-tapping activities against Merkel that infuriated her, representatives of the US government denied allegations that even allies were on the US' list of targets.
But in an interview with ABC's Fusion network on Monday, Obama said that the US is reassessing its national security operations to ensure that the growing technical capability of the National Security Agency (NSA) remains "under control."
NSA Director General Keith Alexander and his deputy Chris Inglis, Director of National Intelligence James Clapper and Deputy Attorney General James Cole were set to testify at an open hearing of the House Intelligence Committee on Tuesday.
Their testimony would cover NSA operations and potential changes to the Foreign Intelligence Surveillance Act, which regulates electronic spying.
"It is hard to rebuild the trust since the US will unlikely stop eavesdropping. But the US can gain by promising not to spy on major governments and people of Europe," Liu Weidong, an associate research fellow with a top think tank in Beijing, the Institute of American Studies at the Chinese Academy of Social Sciences, told the Global Times.
Other countries will now learn to improve their defense technology against such spying, Liu said.
US Senator Dianne Feinstein, who herself is a member of Obama's Democratic Party, said the Senate Intelligence Committee she chairs had not been informed of the NSA's spying activities and voiced her opposition to the operations.
"With respect to NSA collection of intelligence on leaders of US allies - including France, Spain, Mexico and Germany - let me state unequivocally: I am totally opposed," Feinstein said on Monday in a statement to reporters.
She also asked for a "major review" of all intelligence-gathering programs.
A European Parliament delegation on Monday met with House Intelligence Committee chairperson Mike Rogers and discussed the need to rebuild trust.
The delegation would meet with more US officials on Tuesday and Wednesday.
To protect its citizens from alleged US spying, Brazil insists on a plan that requires global Internet companies to store data of Brazilian users inside the country, Reuters reported on Tuesday.
But some analysts still doubt American intentions.
"Despite these responses made to the allies' outrage, the US is not likely to end its spying operations. Even if it does, it will restart the programs later," Xin Qiang, a professor of the Center for American Studies at Fudan University, told the Global Times on Tuesday.
Agencies contributed to this story