JOHANNESBURG (AP) — The World Health Organization has declared an end to the yellow fever outbreak that killed about 400 people in Congo and Angola, calling it "one of the largest and most challenging" in recent years.

The WHO statement Tuesday says 965 cases were confirmed but thousands of others had been suspected. Neither country had reported a new confirmed case in the past six months.

Angola in late December declared an end to its outbreak, and Congo made its announcement Tuesday.

The global health agency said more than 30 million people were vaccinated in emergency campaigns to control the outbreak in the two neighboring countries, which have among the world's weakest health systems.

"This unprecedented response exhausted the global stockpile of yellow fever vaccines several times," WHO said.