The Bill & Melinda Gates Foundation announced Wednesday that it will spend $50 million to support emergency response to the Ebola outbreak in West Africa, marking the group's largest donation to a humanitarian effort.

"It became clear to us over the last seven to 10 days that the pace and scope of the epidemic was increasing significantly," Chris Elias, president of global development for the world's largest charitable foundation, told The Associated Press.

The Seattle-based foundation said the money will go to the United Nations, the World Health Organization, the U.S. Centers for Disease Control and Prevention and international organizations involved in fighting transmission of the virus.

The money will be used to purchase supplies and to develop vaccines, therapies and better diagnostic tools. The foundation wants to help stop the outbreak as well as accelerate development of treatments and improve prevention.

The foundation was particularly influenced by the request on Friday by U.N. Secretary-General Ban Ki-moon for $600 million to fight the Ebola outbreak.