President Barack Obama said all but 100 U.S. troops would withdraw from the battle against Ebola in Liberia by the end of April. At the peak of the largest Ebola outbreak in history, there were 2,800 troops in the West African nation.

About 1,500 troops have already returned from West Africa and have completed or are undergoing 21-day quarantines. Obama said the U.S. response to the outbreak would not end until the number of Ebola cases reaches zero.

“Our mission is not complete. Today, we move into the next phase of the fight — winding down our military response while expanding our civilian response,” Obama told reporters and volunteers at a White House Ebola news conference.

Obama said about 10,000 “civilian responders” would remain to fight the potentially deadly infection, according to multiple reports.

In financial terms, the U.S. has been the biggest contributor to the fight against Ebola, spending $939 million, according to an NPR report. About 1/3 of the money was spent on military response.

The news of a military withdrawal came as the number of new Ebola cases in West Africa, the epicenter of the outbreak, rose for the second consecutive week. The World Health Organization (WHO) said there were 144 news Ebola cases. Sierra Leone registered 76 cases, Guinea 65 and Liberia three.

“Despite improvements in case finding and management, burial practices, and community engagement, the decline in case incidence has stalled,” the WHO said. “The spike in cases in Guinea and continued widespread transmission in Sierra Leone underline the considerable challenges that must still be overcome to get to zero cases. The infrastructure, systems, and people needed to end the epidemic are now in place; response measures must now be fully implemented.”

BLU-MED Response Systems® has been on the front line in the battle against Ebola. In September, a German humanitarian group deployed two BLU-MED mobile hospitals with Ebola isolation units to Liberia.

At the height of the Ebola outbreak in August and September, Liberia registered 300 new cases a week. That figure has dropped a hundredfold in the months since.

In a little more than a year, almost 23,000 people have been infected, and more than 9,000 have died.