Omar Sobhani / Reuters Afghan President Hamid Karzai speaks during the last day of the Loya Jirga, in Kabul Nov. 24, 2013.

A U.S. general phoned President Hamid Karzai to apologize for a drone strike in Afghanistan on Thursday that killed and wounded civilians—a fact that the military concealed—a coalition official said Friday, according to the New York Times.

The attack came at a time when talks between Afghanistan and the U.S. over a long-term security agreement had reached an impasse. The U.S. has warned Karzai that if he does not sign the agreement, American and NATO forces will plan for a full withdrawal next year.

Gen. Joseph F. Dunford Jr., the American and NATO commander in Afghanistan, made the late-night phone call to the Afghan President after Karzai’s publicly lashed out at his American allies for the attack.

Mr. Karzai vowed this week that he would cancel the security agreement completely if there was just one more raid that killed civilians. The drone strike seems to be the last straw.

“For as long as such arbitrary acts and oppression of foreign forces continue, the security agreement with the United States will not be signed,” he said.

[NYT]