Carter: Apparent suicide bomber kills 4, injures 17 at U.S. base in Afghanistan

Two U.S. servicemembers were among the four people killed and 14 injured in an explosion inside Bagram Airfield, a large U.S. base north of Afghanistan, NATO said early Saturday morning.

U.S. Army Gen. John Nicholson confirmed the number of injuries and said the blast was caused by an “explosive device.” ​

Secretary Ash Carter later said in a statement an apparent suicide bomber is responsible for the explosion that killed  two U.S. servicemembers and two U.S. contractors working on the base. Sixteen other U.S.  servicemembers and one Polish soldier were injured.

The explosion occurred north of Kabul, the Afghan capital, and forced medical response teams rush to the scene. "Response teams at Bagram continue to treat the wounded and investigate the incident," NATO said in a statement.

The identities of the victims were not disclosed.

In a message posted by a spokesman on Twitter, the Taliban claimed responsibility for the blast, which comes days after an attack on a German consulate killed at least six people and wounded over 100 others in the northern city of Mazar-i-Sharif. The extremist group said it was "revenge attack" for recent U.S. airstrikes in the region.

Zabihullah Mujahid, a spokesman for the insurgent group, said the attack had been planned for four months.

Earlier this week, extremists celebrated U.S. President–elect Donald Trump’s stunning victory, hoping his triumph will “lead to civil war,“ according to a jihadist monitoring group.

"Rejoice with support from Allah, and find glad tidings in the imminent demise of America at the hands of Trump,” said the al-Minbar Jihadi Media network, which is affiliated with the Islamic State, according to the U.S.-based SITE Intelligence Group.

"Trump’s win of the American presidency will bring hostility of Muslims against America as a result of his reckless actions, which show the overt and hidden hatred against them,” the al- Minbar Jihadi Media network continued.

In light of the attack on the airfield and an attack two days ago on the German Consulate in Mazar-e-Sharif, the U.S. Embassy in Kabul was being closed for routine services on Sunday.

The embassy also cautioned U.S. citizens "of the serious threat of violence, kidnapping andhostage taking in Afgnistan."

Contributing: JaneOnyanga-Omara and The Associated Press.