"In the last couple weeks there's been an increased threat," Odierno said. "We've increased our security on some of our bases. We have also increased activity with the Iraqi Security Forces."
The general said the group's signature weapon is the Improvised Rocket-Assisted Munitions, which basically consists of a propane tank packed with explosives that is attached to a 107-millimeter rocket often launched from the back of a pickup truck.
Kataib Hezbollah is an Iraqi Shiite organization that has the backing of Iran's influential Revolutionary Guard, The Washington Post reported. Members apparently crossed into Iran to receive training from the Guard and have since returned to cause trouble in conjunction with U.S. troop withdrawals.
Odierno said Kataib Hezbollah's goal was to attack U.S. forces and was not considered a long-term threat to Iraq's security.
2014: The Year in Music [PHOTOS]