Esper says it's crucial S.Korea pays more for U.S. troops

Speaking after a high-level defence policy meeting with his South Korean counterpart, Jeong Kyeong-doo, Esper also said the two countries must be flexible with their joint military drills to back diplomatic efforts to end North Korea's nuclear programme.

But he stopped short of announcing any new reduction in military exercises that North Korea has sharply condemned.

North Korea said on Thursday it had turned down a U.S. offer for new talks ahead of a year-end deadline Pyongyang has set for Washington to show more flexibility in negotiations.

As uncertainty hangs over the troubled peace push, the United States and South Korea are simultaneously scrambling to clinch an agreement in the coming weeks to cover next year's costs of maintaining a 28,500-strong U.S. military presence aimed at deterring North Korea.

South Korea, Esper said, "is a wealthy country and could and should pay more" for the U.S. military deployment.