"We are extremely thankful for the contributions of all these individual countries, " Matern said.

CNN: Coalition nations leave Iraq as security improves

Matern said the other nations whose troops remain in Iraq with the coalition will be negotiating similar agreements with the government.

CNN: Coalition nations leave Iraq as security improves

"Additionally coalition forces will realign battle space as necessary based on the composition of the coalition, the readiness of the Iraqi security forces and the threat situation, " Matern said.

CNN: Coalition nations leave Iraq as security improves