Liberia President Ellen Johnson Sirleaf says the Ebola outbreak, which killed more than 4,000 people in Liberia and raised health concerns here in the city, scared her as she struggled to figure out ways to stop its spread.

President Ellen Johnson-Sirleaf calls the virus that invaded her small West African nation an unknown enemy that came in and wreaked havoc last summer.

"Horrifying. Horrifying," she said. "I was as frightened as everybody else because we didn't know what to do, we didn't know how to respond. This was a strange, unknown enemy."

In an exclusive interview with NY1 at York College, she candidly admitted that her administration was caught off guard.

"When the virus entered our capital city and entered in a few of the communities that are really crowded," she said, "it was total chaos."

Chaos that the world immediately took note of, especially when Ebola crossed the Atlantic and cases were reported in the United States, including New York City. But President Sirleaf said she forewarned global leaders that Ebola was more than her government could handle. 

"I had written President Obama and Britain, all of them, and tried to tell them that this was not a threat to Liberia, it wasn't a threat to West Africa. It was a global threat, and if they did not respond, chances are there would be people crossing borders, going into other countries, and indeed, it did happen." she said.

In September, 42-year-old Thomas Eric Duncan, a Liberian national, flew to Texas and was diagnosed with Ebola days later. Before he died on October 4, he had infected two nurses, who were isolated and successfully treated.

Weeks later, New York City physician Dr. Craig Spencer was infected after returning from volunteering with Doctors without Borders in Guinea. His isolation at Bellevue sparked a wave of hysteria.

Sirleaf readily admits that she and her administration were harshly criticized, but she said she finally convinced world leaders to step in during an emergency conference call with United Nations Secretary-General Ban Ki-moon.

"I took charge of the presidential task force," Sirleaf said. "I said, 'I will take responsibility for this.'"

We'll explain how she said she finally got a handle on the Ebola crisis in part two of our exclusive report.