After more than six months of controversy over U.S. surveillance policies, President Obama will deliver a highly anticipated address Friday morning outlining how he intends to restore trust in the National Security Agency and in the government’s ability to balance national security and privacy interests.

In the speech, which Obama will deliver around 11 a.m. from the Justice Department, the president is expected to announce some new limits on NSA, but also to call on Congress to help determine the extent of any new restraints on the agency’s most controversial practices. He will be speaking both to domestic and global audiences that have joined an unprecedented debate about the proper scope of U.S. surveillance.

Current and former officials familiar with Obama’s plans said he will authorize some new privacy protections for foreigners whose data is collected by the NSA and will propose the establishment of a public advocate to represent privacy interests before the Foreign Intelligence Surveillance Court.

He is not, however, expected to end the NSA’s collection of data on virtually all Americans’ phone records — part of a program that has generated perhaps more controversy than any other since it was disclosed in June. Rather, Obama, officials said, will ask Congress to deliberate on the appropriate boundaries for the phone records collection.

Intelligence officials have said that program is a critical tool in their efforts to prevent attacks on the United States. Some analysts have argued that, although a review panel appointed by the White House recommended that the NSA shift control of phone data to phone companies or a private third party, it found no violation of the law by the agency.

“We’re not talking about trying to fix a massive breach of Americans’ privacy,” said Gary Schmitt, a resident scholar and national security expert at the American Enterprise Institute. “When you begin with that, then you can make judgments about how important the current collection system is for national security. But you shouldn’t do it under this shadow of a Big Brother that doesn’t exist.”

To civil liberties groups and privacy advocates, disclosures about the NSA have revealed a government that has leveraged new technologies to reach further into Americans’ privacy than ever before. Many are hoping that whatever changes Obama announces will be more than cosmetic.

“We’re looking to the president to make very bold statements about reclaiming privacy,” said American Civil Liberties Union’s legislative counsel Michelle Richardson.

Richardson said that, although a number of ideas for reform have been floated by the White House review group and others, Obama’s decision on the NSA’s bulk collection is the issue he will be measured on — “not just by the ACLU, but by history.”

The NSA’s harvesting of phone data began after the Sept. 11, 2001, terrorist attacks and was placed under court supervision in 2006. The program collects metadata, or phone numbers dialed and call lengths and times, but not call content. Analysts are supposed to access the data only for the purpose of seeking leads in counterterrorism investigations.

The program’s disclosure in June marked the start of a string of revelations about U.S. surveillance policies, most of them based on leaks from former NSA contractor Edward Snowden.

A Washington Post-ABC poll conducted in November found nearly 70 percent of respondents said the NSA’s surveillance of telephone call records and Internet traffic intrudes on some Americans’ privacy rights.