U.S. Defense Secretary Robert Gates has warned NATO members that they must increase their defense spending commitments to the alliance.
Gates spoke at NATO headquarters in Brussels Friday, in what is expected to be his last major policy speech before retiring at the end of the month. He said U.S. lawmakers are losing patience with covering three-quarters of defense spending for the coalition.
Gates noted that all 28 NATO members voted for the mission against Libyan leader Moammar Gadhafi, but fewer than half have participated.
He said unwillingness or inability to contribute has also affected operations in Afghanistan, where he said the coalition has "struggled, at times desperately" to sustain a deployment of up to 45,000 troops.
He said finishing the mission in Afghanistan must be done in a united way, not dictated by each member's domestic financial situation.
And he said if other nations fail to step up their contributions to the more than 60-year-old transatlantic alliance, future U.S. administrations might not consider the return on its investment worth the cost.
Gates said Thursday that substantial military progress is being made on the ground in Afghanistan, but warned that those gains could be threatened if the transition to full Afghan government control of security is not made in a deliberate, organized and coordinated manner.