The presidents of South Korea and the United States yesterday agreed to move forward the long-delayed ratification of the free trade agreement between the two countries, Seoul officials said.

In a summit in London, Lee Myung-bak and Barack Obama also pledged to push for a "stern, unified" international response against North Korea if it goes ahead with the planned rocket launch.

Obama told Lee that the United States is preparing for a UN Security Council resolution to sanction North Korea, according to Lee's spokesman Lee Dong-kwan.

Their first meeting took place just before the Group of 20 financial crisis summit.
 
"The two presidents agreed that the Korea-S'>US FTA will be mutually beneficial to the two countries and pledged to move forward the agreement," the spokesman told reporters after the 30-minute talks.

The Obama administration had called for a renegotiation of the FTA, which was signed in 2007 and has yet to be ratified by both countries' legislatures.

During his presidential campaign, Obama called it "badly flawed," demanding measures to address the imbalance in the auto trade.

Seoul has ruled out any renegotiation.

Seoul officials said the S'>US administration has recently shifted its position and has been considering the deal in a more positive light.

"The two leaders recognised the result of working-level coordination between the two countries over the FTA," a Cheong Wa Dae official said on condition of anonymity before their summit.

President Obama expressed strong willingness to make progress in the trade deal, while Lee emphasised its importance in the two counties' alliance, the spokesman said.

Seoul officials did not elaborate on whether it meant that the Obama administration will withdraw its demand for renegotiation.

On March 10, S'>US trade representative Ron Kirk told a Senate hearing that Washington was ready to "step away" from the FTA if problems remained unaddressed.

Lee and Obama also agreed to deal sternly with North Korea's impending rocket launch, which they regard as a serious threat to peace and stability in Northeast Asia.

They denounced the test-firing as a violation of a 2006 UNSC resolution which bans its activities related to ballistic missile programmes.

"The two presidents agreed on the need for a unified reaction by the international community, such as referring the matter to the UN Security Council," the spokesman said.

The two countries had ruled out military responses, such as shooting it down, and will instead focus on economic sanctions, Seoul officials said.

On Wednesday, Japanese Prime Minister Taro Aso told Lee that Tokyo would seek a new UN resolution against North Korea.

Obama also told Chinese President Hu Jintao that Washington would refer the issue to the UN Security Council.

China and Russia are reportedly reluctant to push for new sanctions because the UNSC resolution specifically refers to missile activities and does not cover space launch vehicles as claimed by the North.

North Korea said it will launch a communications satellite into orbit between April 4 and 8 as part of a peaceful space development programme.

Seoul, Washington and Japan regard it as a disguised test of the Taepodong-2 intercontinental ballistic missile.

Even if the rocket is loaded with a satellite, not a missile, the allies see it as a breach of the UN resolution, because both are based on the same technology.

CNN television reported yesterday that Pyongyang has begun fueling the rocket in its launch site. It can be fired about three to four days after fueling begins.

Lee and Obama also reaffirmed their commitment to the goal of a complete and verifiable dismantlement of North Korea's nuclear programs though the six-party talks, which have been stalled since late last year over differences on verification protocol.

The two leaders agreed to meet again in Washington on June 16 and Obama accepted Lee's invitation to visit Seoul later, Kim Eun-hye, Lee's deputy spokeswoman said.

The two leaders had two phone calls since Obama's election in November.

Standing before Korean reporters ahead of the start of the summit, Obama hailed Korea as one of "America's closest allies and greatest friends." He expressed gratitude for Seoul's support for S'>US efforts in Afghanistan.

They also discussed diverse measures to overcome the economic crisis and promote bilateral alliance and cooperation.

They agreed on the need to expand global trade and stem protectionism to pull the world out of its slump.

They vowed to call for world leaders to coordinate their stimulus plans and disposal of distressed financial assets.

They also agreed that the two countries would further discuss extending their currency swap arrangement to stabilize finance.

In February, the S'>US Federal Reserve decided to extend a S'>US$30 billion swap line agreed last October for another six months until Oct. 30.

The two countries will expedite work to formulate a new "21st century strategic alliance" vision that will expand their military cooperation and deepen ties in politics, economics, diplomacy, culture and other areas.