South Korean President Lee Myung-bak and U.S. President Barack Obama on Thursday agreed the alliance between the two countries is firmer than ever and that the already strong relations will get a significant boost from a landmark free-trade agreement. The trade pact, security alliance and North Korea were among the key topics at the White House summit held a day after Congress gave its final approval of the long-pending pact, which is seen as a watershed upgrading the six-decade-old military alliance between Seoul and Washington.