Afghanistan: Insider attack kills one American, wounds four; Suicide bombers kill Nineteen Afghans, including eight children

A U.S. contractor was killed and four U.S. soldiers were wounded in Afghanistan on Friday in an apparent insider attack, shortly before U.S. Defense Secretary Chuck Hagel arrived on his first visit to the country.

Three men in Afghan uniforms, driving an Afghan security force vehicle, forced their way into a U.S. base and opened fire on their victims.

Investigators said they were nearly certain it was an insider attack because the gunmen came from the Afghan side of the joint U.S.-Afghan base and rammed an Afghan military vehicle through a checkpoint dividing the base before they leaped out of the vehicle and gunned down their victims.

Additionally, on Saturday, two separate suicide attacks - one, on the Afghan Defense Ministry in Kabul, and one, near the city of Khost - left nineteen Afghans dead, including eight children.

The Taliban claimed responsibility for the attack on the Afghan Defense Ministry in Kabul, and said the attack was a message to Mr. Hagel that they have the capability to strike the capital city - even while he was there. However, the Taliban said it did not carry out the previous day's attack on the joint U.S.-Afghan base, which, as mentioned earlier, appears to have been an insider attack. Thus far, the Taliban have not claimed responsibility for the attack near Khost.

As the U.S. military continues to heed President Obama's directive to withdraw from Afghanistan and hand over security to the Afghan forces, the steady, ongoing stream of violence continues to raise the question as to whether the Afghan forces are capable of securing the country after Obama completes his bolting exit from Afghanistan.