WASHINGTON — The Army said Wednesday that it had mistakenly sent 7,000 letters with the salutation “Dear John Doe” to family members of soldiers who have died in the wars in Iraq and Afghanistan.

The letters were supposed to have carried personal greetings. The Army said that the mistake was the fault of a subcontractor who printed the letters, but that the service bore ultimate responsibility because it did not check the letters before they were mailed.

The Army said that its chief of staff, Gen. George Casey Jr., would be sending 7,000 personally addressed letters of apology.