U.S. airstrike

The recommendation came just days after a deadly U.S. airstrike "mistakenly" hit a hospital during fierce fighting in the north.

Gen. John F. Campbell told Congress that conditions on the ground have changed since Obama announced his plan in 2014 to cut the current U.S. force of 9,800 to an embassy-based security contingent of about 1,000 in Kabul post-2016. 

A spokesman for Central Command, Air Force Col. Patrick Ryder, told reporters at the Pentagon on Friday that the hacker, Junaid Hussain, also was responsible for the recent release of personally identifying information on about 1,300 U.S. military and government employees and sought to inspire violence against U.S. service members.

Ryder called Hussain a key IS member. He said he was killed Monday in an airstrike in Raqqa, the city the Islamic State group considers its capital.

The airstrike killed Abu Khalil Al-Sudani on July 11, Carter said in a brief statement given to reporters traveling with him in Iraq.

Carter called Al-Sudani a senior shura member and head of Al-Qaida suicide and explosive operations, and said he is directly linked to plots to attack the United States.

He said Al-Sudani also directed operations against coalition, Afghan and Pakistani forces, and maintained a close association with Ayman Al-Zawahiri, the leader of Al-Qaida.

U.S. officials confirmed they carried out the strike, but declined to say whether they killed the leader.

The strike in Nangarhar province killed Islamic State affiliate leader Hafeez Sayeed and others on Friday, said Abdul Hassib Sediqi, a spokesman for Afghanistan's National Directorate of Security. 

Sediqi said Afghan intelligence officials provided information to U.S. forces, who carried out the strike.