Federal prosecutors say a retired State Department official and his wife who admitted they spied for Cuba did not fully cooperate with investigators, but the government says it will still honor its end of the couple's plea agreement.

Walter Kendall Myers and his wife, Gwendolyn, are scheduled to be sentenced Friday in U.S. District Court in Washington.

As part of a November 2009 plea deal, the 73-year-old Myers agreed to a sentence of life in prison and his wife agreed to a sentence of up to 7 1/2 years. They admitted they had worked for Cuban intelligence for more than 30 years.

That agreement was contingent upon the pair's cooperation with authorities.

In a pre-sentencing memorandum filed last week, prosecutors said some of the couple's debriefings with FBI officials were "marred by both of the defendants' lack of recollection or inconsistencies and contradictions."

The document also said Myers at times "gave inconsistent or uncooperative responses or was intentionally withholding information."

Prosecutors, however, said that trying to show the pair broke the plea deal could harm national security interests because of information that could be revealed in court.

It is "plainly not in the national interest" to seek a longer sentence for Gwendolyn Myers, 72, the government's filing said.

Prosecutors asked the court to sentence her to 7 1/2 years in prison, the maximum under the agreed range.

The court should consider the "limited value of the defendants' cooperation" in her sentencing, prosecutors said. They also said she was "far more than just a knowing 'wife of a spy.' "

In their own sentencing memorandum, however, defense attorneys said the couple "participated in hundreds of hours of debriefings, both before and after the plea, and have attempted honestly and to the best of their ability to answer every question put to them" since their June 2009 arrest.

The defense asked the court to sentence Gwendolyn Myers to six years in prison, saying she was only "a secondary participant" who did not have access to classified information. Because of her age, defense attorneys said, there is no risk of her repeating the offense.

Defense attorneys also requested that the couple be assigned to prisons located near each other so family can visit more easily.