JACKSONVILLE, Fla. -

About 235 pounds of cocaine with an estimated street value of $3.47 million was seized from the Port of Jacksonville last month, U.S. Customs and Border Protection announced Thursday.

While inspecting maritime cargo containers at the port, customs agents identified a suspect container that they said showed signs of tampering. The agents said they examined the contents of the container and found 100 bricks of cocaine.

The drugs were packaged inside four black duffel bags located on top of the cargo, agents said. They said a canine officer also alerted them to the presence of drugs.

One of the bricks was tested by officers and the substance tested positive for cocaine.

The case is still under investigation and no arrests have been made at this time, investigators said.

They said the container arrived in Jacksonville aboard a freighter from Panama and originated in Chile.

Agents said they had to keep the drug bust under wraps for a month as they followed leads to learn who tried to smuggle it in.

Douglas Straatsma, of Customs and Border Protection, said agents are always looking for drugs and other illegal contraband at JaxPort, a place where hundreds of thousands of shipping containers come and go each year. From time to time, they make busts, but rarely like this one, he said.

"We knew that this was occuring in other ports," Straatsma said. "We were following their lead on this, and we were just looking at these ships that follow these itineraries, knowing that the potential was there."