Via NBC News: Former First Lady Nancy Reagan Dead at 94:

Former first lady Nancy Reagan has died, according to a spokeswoman with the Reagan Library. She was 94.

The cause of death was congestive heart failure, according to her rep Joanne Drake. "Mrs. Reagan will be buried at the Ronald Reagan Presidential Library in Simi Valley, California, next to her husband, Ronald Wilson Reagan, who died on June 5, 2004," Drake wrote in a statement.

"Prior to the funeral service, there will be an opportunity for members of the public to pay their respects at the Library."

"It is a very sad day," former Ronald Reagan Chief of Staff Ken Duberstein told NBC News.

In lieu of flowers, Mrs. Reagan asked that contributions be made to the Ronald Reagan Presidential Library and Foundation at www.reaganlibrary.com, Drake said.