WASHINGTON (AP) — President Barack Obama describes says new screening measures at key international airports are “just belt-and-suspenders” to add a layer of protection to measures already employed.

He says the new measures will include more screening questions for passengers arriving from the countries worst hit by the outbreak — Liberia, Sierra Leone and Guinea. He says the procedures will allow United States officials to isolate, evaluate and monitor travelers and collect any information about their contacts.

He says the case of Ebola in the U.S. — a patient who died Wednesday in Dallas — illustrates that “we don’t have a lot of margin for error.” But he said chance of an Ebola outbreak in the U.S. “remains extremely low.

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