Monrovia , Liberia ( CNN ) -- The general and his soldiers have spent more than a decade at war in Iraq and Afghanistan but this could be one of their toughest battles yet . Their enemy this time is not soldiers or militants . It is Ebola -- invisible and killing thousands in Liberia . Maj. Gen. Darryl Williams , the commander of U.S. Army Africa who is leading the advance team into Liberia , says the mandate here -- straight from President Barack Obama -- is different from other missions . `` We were brought in to provide our unique capabilities and fill the gaps , '' the two-star general says . In other words , Williams and his troops are here in a supporting role and not a leading one . Fight ready . But Williams -- who still remembers his college game when he tackled American Football Hall of Famer Dan Marino -- also looks and sounds like he 's ready for this fight . As two Osprey military aircraft appear on the horizon , signalling the opening of an air bridge from Senegal that will put more U.S. troops on the ground in Liberia , Williams ca n't contain his excitement . `` You want to know where the U.S. military is ? It 's right here , '' the general says , pointing skyward . But tackling Ebola is a tough task and six months after the start of the unprecedented outbreak , critics say the international response continues to be woefully slow . At Liberian government-run Ebola care units , overcrowding has forced patients to sleep on the floors and many healthcare workers who say they 've gone weeks since their last pay checks are now threatening to strike . `` There is no question in my mind that we are making an impact , '' the U.S. unit 's chief medical officer , Colonel Jim Czarnik says . `` It is about doing it quickly but you do n't want to sprint to failure. `` Game changer . Czarnik points to four recently opened Ebola testing labs , run by military personnel that are already making a difference . Thanks to one lab in Bong County , patients now wait hours , not days to get test results . This means patients who test negative spend less time in isolation with those that test positive . `` It 's a game changer , '' says Sean Casey , project manager at a care center run by the International Medical Corps charity that sits just minutes down the road from the U.S . Naval laboratory . `` Patients were afraid at one point of coming to an Ebola treatment unit because they were afraid of becoming infected . Now that we have the lab , patients can get the results back within hours . '' But there are just four labs in a country where nearly 1,000 cases of Ebola have been confirmed . As Williams inspected the construction of the Monrovia Medical Unit , a facility specifically for infected health workers to be run by U.S. government health teams , a crowd of local residents monitors progress from just across the road . `` While we 'll do a lot of tangible things -- we 'll build this hospital , we 'll build the Ebola treatment units , provide these labs -- there 's a lot of intangible nature to this fight , '' he said . You want to give people the resilience , the hope that they can fight this thing and see this through . '' His U.S. Army Africa advance team is tiny compared to the 101st Airborne that will be replacing them in the coming weeks . President Obama has authorized up to 4,000 troops to West Africa and since mid-September the few hundred soldiers , sailors and airmen and women in Liberia have been laying the groundwork to make sure that larger force has the housing , medical and logistics in place when they begin to arrive . `` Soldiers are used to moving toward the sounds of the guns . These are the loudest guns that the world has heard in a long time . `` There is no better fight worth fighting then the one in Liberia right now , '' says Czarnik . Complete coverage on Ebola .
U.S. military advance force building facilities to battle Ebola . One lab speeds up diagnosis . Another facility will treat stricken healthcare workers in Liberia . Air bridge with Senegal opens to bring in more troops .