President Obama proposed new safeguards for the government's vast surveillance of communications in the U.S. and abroad, adding additional judicial review and disclosure requirements, but largely leaving in place programs that he said were needed to "remain vigilant in the face of threats."

His proposals, unveiled in a long-anticipated speech on Friday, drew warm reviews from intelligence officials, but expressions of disappointment from many civil liberties activists and some prominent technology company executives.

Under Obama's plan, the Maryland-based National Security Agency still would have broad authority to intercept e-mail and other Internet communications overseas, even when its dragnet pulls in the communications of Americans who are corresponding with foreigners. Intelligence officials say this power has been key to counter-terrorism investigations.

Obama proposed more significant changes for the program that has generated the most public controversy: The government's database on nearly all telephone calls in the United States, which shows when calls took place and which numbers are connected to which other numbers.

Under Obama's plan, the government no longer would hold the so-called telephony metadata, but he left undecided who would. Telephone companies have resisted taking on the cost and liability of holding the data themselves, and some prominent members of Congress say that involving a private party would increase the risk of leaks and other problems.

Rep. C.A. Dutch Ruppersberger, the top Democrat on the House Intelligence Committee, said in a statement that he agreed with "many" of the president's proposals — but did not specify which ones.

Ruppersberger's district includes NSA headquarters at Fort Meade. The Army base in Anne Arundel County is the state's largest workplace.

"The solution to regaining the public's trust will center on strengthening oversight, promoting transparency and safeguarding Americans' civil liberties," he said. "These are not mutually exclusive goals."

Obama intended his speech to quell concerns about U.S. spy practices. He said he recognized the unease many Americans have felt in the seven months since former NSA contractor Edward Snowden began to reveal details about the agency's activities.

Obama pledged greater transparency, and said leaders could not simply say: "Trust us, we won't abuse the data we collect."

But he staunchly defended the nation's intelligence agencies, saying they had not misused their vast powers in the effort to detect and disrupt terror plots.

After repeated reviews, "nothing that I have learned," Obama said, "indicated that our intelligence community has sought to violate the law or is cavalier about the civil liberties of their fellow citizens …. They are not abusing authority in order to listen to your private phone calls or read your emails."

He told listeners the country faces "real enemies and threats, and that intelligence serves a vital role in confronting them."

Obama gave the Justice Department and the Director of National Intelligence until March 28 to decide who would hold the telephone data. He left unanswered the question of whether the government would continue to collect the data if no solution is found. Officials said that issue had not yet been decided.

In a related decision, Obama surprised some intelligence officials by directing that for now, they seek a judge's approval before mining the voluminous cache of records.

The president added that to his speech less than a day before delivery, officials said. But the last-minute move was an exception. Most of Obama's proposals resulted from months of negotiations within the administration and were carefully honed to avoid interfering with the work of the intelligence community.

"We think these are reasonable, moderate steps," said one senior intelligence official who was involved in negotiations with the White House and asked for anonymity in order to speak freely.

By contrast, civil liberties advocates and officials of technology companies had hoped Obama would go further in curtailing surveillance.

"We are disappointed that President Obama chose not to end the NSA's bulk collection of Americans' phone call records, nor to provide any specifics on how he would significantly alter it," said Virginia Sloan, president of the bipartisan Constitution Project. "We hope to see Congress act decisively to end all bulk collection of our private records. …

"As long as the NSA continues to hold this sensitive data, or to map and sift through it without tighter restrictions, the phone call collection program poses an unacceptable threat to our fundamental freedoms."