US President Barack Obama said Wednesday the BP 'static kill' effort to plug the runaway Gulf of Mexico oil well appeared to be working, calling this 'welcome news.' 'It was very welcome news when we learned overnight that efforts to stop the well, through what's called a static kill, appear to be working and that a report out today by our scientists show that the vast majority of the spilled oil has been dispersed or removed from the water,' Obama said. 'So, the long battle to stop the leak and contain the oil is finally close to coming to an end. And we are very pleased with that. Our recovery efforts, though, will continue. We have to reverse the damage that's been done.' Obama's comments came after the first part of BP's long-awaited static kill was conducted overnight: heavy drilling fluid was rammed into the busted Macondo well for eight hours, forcing the oil back down into the reservoir miles beneath the seabed. 'The MC252 well appears to have reached a static condition -- a significant milestone,' BP said. 'The well pressure is now being controlled by the hydrostatic pressure of the drilling mud, the desired outcome of the static kill procedure.' Now officials must decide whether to permanently seal the reservoir with cement right away or wait until a relief well is finished mid-August -- this will depend on whether there are any leaks in the steel casing of the well. Separately, US officials announced that about three-quarters of the oil spilled from the well has already evaporated, dispersed, or been burned off or captured. 