President Barack Obama left Seoul, where he met with his South Korean counterpart Lee Myung-bak on Thursday, wrapping up his four-nation Asia trip.

Before he flew home from the U.S. air base at around 04:00 p.m. (0700 GMT), he met with 1,500 U.S. military service members dispatched here, giving an address to them.

"America's commitment to the defense of the Republic of Korea (South Korea) will never waver and our alliance has never been stronger," Obama said, lauding his armed forces' services in the nation.

Earlier in the day, Obama met with his counterpart Lee on ways to strengthen their alliance, to denuclearize the Korean Peninsula, and to move forward on the bilateral free trade pact.

At the joint conference held with Lee, Obama also announced that Stephen Bosworth, special U.S. representative for the DPRK policy, will visit Pyongyang on Dec. 8 in a bid to prod the nation back to the six-party talks.

The Lee-Obama meeting is the third of its kind since Obama's inauguration in February.