President Lee Myung-bak called on advanced nations Wednesday to make sure to carry out their aid commitments to developing nations, stressing that less well-off nations are not a burden, but key partners for sustainable growth of the global economy. Lee made the appeal during a speech at the opening ceremony of the Fourth High Level Forum on Aid Effectiveness, the largest international conference on development assistance. This year\'s meeting in the port city of Busan drew about 3,000 government representatives and experts from 160 countries around the world.