WASHINGTON - The Obama administration has asked the U.S. Congress to extend three surveillance techniques for intelligence agencies tracking suspected militants that expire this year, according to a letter to lawmakers.

Approved after the September 11 attacks in 2001 at the request of the Bush administration, techniques such as roving wiretaps and accessing all kinds of personal records drew criticism from civil liberties groups and some lawmakers who said they were unconstitutional and violated privacy rights.

In the letter released on Tuesday, a Justice Department official asked that three of the techniques expiring on December 31 be renewed and said the Obama administration was open to lawmakers' plans to add more privacy protections.

"The administration is willing to consider such ideas, provided that they do not undermine the effectiveness of these important authorities," Assistant Attorney General Ronald Weich said in a letter to Senate Judiciary Committee Chairman Patrick Leahy and the ranking Republican senator, Jeff Sessions.

The committee will hold a hearing next week to discuss the administration's request.

"I am pleased that the Justice Department has signaled its willingness to work with Congress in addressing the expiring provisions," Leahy said. "It is important that Congress and the executive branch work together to ensure that we protect both our national security and our civil liberties."

The Justice Department specifically asked that Congress reauthorize the use of roving wiretaps, permitting authorities to track multiple communications devices owned by an individual since people can switch devices frequently and quickly.

The administration also asked that one particularly controversial intelligence gathering method be reauthorized -- accessing personal records.

That was a point of contention because some feared that even library and bookstore records could be accessed, prompting Congress to try to limit it.

"CAUTIOUSLY OPTIMISTIC"

"Many of these instances will be mundane," Weich said, suggesting that requests often are for driver's license records protected by state privacy laws. But he acknowledged others would be more complex and tracking their business activities.

The administration also asked to continue being able to track suspected foreign militants who may be working individually rather than as part of a larger group, much like Zacarias Moussaoui who is serving a life sentence for conspiring with the September 11 hijackers.

While extending controversial Bush policies could annoy President Barack Obama's more liberal backers, the American Civil Liberties Union said the willingness of his administration to enhance privacy protections was a good first step but would depend on the outcome.

"We're cautiously optimistic. There are still changes we'd like to see to these three provisions to protect Americans' privacy," said Michelle Richardson, a legislative counsel for the ACLU.

She said other government surveillance activities that did not expire this year also needed fixing, especially so-called national security letters which were essentially subpoenas for personal records.

The FBI has been roundly criticized for abusing them.

Democratic Senators Richard Durbin and Russ Feingold urged Congress to take up that issue now as well.

"We must take this opportunity to get it right, once and for all," they said in a statement.

(Editing by John O'Callaghan)