Breedlove, who assumed command of U.S. European Command last week, replaced Adm. James Stavridis as the new Supreme Allied Commander Europe Monday, Stars and Stripes reported.
"Within the borders of our alliance we enjoy unprecedented levels of stability, but beyond our frontiers there is uncertainty and insecurity," Breedlove said in a speech at his headquarters in Mons, Belgium. "As [commander], my first and enduring priority will be to ensure that NATO remains vigilant and prepared to meet the challenges and threats of the future with agile, capable, and interoperable military forces."
Heading Breedlove's agenda will be managing transitioning NATO forces from a combat mission in Afghanistan to a support mission focused on training Afghan forces.
Alliance officials say Afghan troops already have leadership roles in most of the country. NATO's combat troops are expected to lead Afghanistan at the end of 2014.
Stavridis, citing an increasingly capable Afghan military and lack of public support for Taliban militants, has said he believes there is little chance of the Taliban retaking control of Afghanistan.
"So, the Taliban don't have the military capability, they don't have a civilian society that will welcome them and they don't have the political capital to take over Afghanistan," Stavridis told the Stars and Stripes in a recent interview. "If I were in the Taliban, I would be very interested in how to come in from the cold."