The U.S. Army chief of staff says cuts in British defense spending may undermine the nation's ability to be an effective ally in future military operations.

Gen. Raymond Odierno says Monday in the Daily Telegraph that the U.S. is reviewing the role of British troops in future conflicts as the U.K. considers reducing military spending to less than the 2 percent of gross domestic product expected of NATO members.

He says: "I would be lying to you if I did not say that I am very concerned about the GDP investment in the U.K."

Prime Minister David Cameron is under fire within his own Conservative Party for failing to promise to end the cuts.