In Sierra Leone, where government officials have asked citizens to stay away from work, the military has deployed at least 750 medical officials to 13 locations, military spokesman Col. Michael Samura said.
Health officials are screening incoming and outgoing passengers at the country's main international airport with a device that takes people's temperature from their eyes at a distance.
People showing signs of fever are quarantined and their blooded is tested.
On Tuesday, Liberia responded to British Airways' decision to suspend service to Monrovia because of the outbreak.
"The government of Liberia regrets that British Airways has suspended flights to and from Liberia until the end of August. However, we fully understand that international airlines must keep the safety of customers and crew as their highest priority," it said.
"We will continue to work around the clock with our international partners to ensure all our key international ports of entry are secure from any transfer of Ebola, both incoming or outgoing."