Nearly 20 pounds of cocaine was seized Saturday evening at Philadelphia International Airport after customs officers made a sweep through an American Airlines  arrival from Jamaica.

Officers discovered two drawstring-style backpacks in the plane's cargo hold concealed behind an access panel, said Steve Sapp, a spokesman for U.S. Customs and Border Protection. Each backpack contained four bricks of a white, powdery substance that tested positive for cocaine.

"It's a pretty sizable seizure," said Sapp. "We usually see people coming through with personal-use amounts."

Customs conducts routine examinations of planes originating from "source nations," Sapp said.

"Most of the time we don't find anything," he said. "But this time we did."

The seized cocaine weighed about 19 pounds, nine ounces and had a street value of $600,000.

Officers have made no arrests.

In June, customs officers seized 14 pounds of cocaine smuggled to Philadelphia from the Dominican Republic. Fabio Dalloco, 45, an Italian national, was arrested and charged with multiple drug counts.