SAN JUAN, Puerto Rico (AP) — The U.S. Coast Guard has removed a total of more than 600 tons (544 metric tons) of oil-covered cargo from a stranded freighter near Puerto Rico, but more work remains to be done, a spokesman said Saturday.

Crews have to remove more debris before pumping the 202-foot (62-meter) ship dry and patching and plugging holes as needed, Chief Petty Officer Paul Roszkowski said in a phone interview.

Crews already have removed an additional 5,000 gallons (18,900 liters) of oil and 22 55-gallon (208-liters) drums of hazardous materials including aerosol cans and batteries, he said.

"'Not one drop of oil has hit the water at this point," he said. "That's great. You don't see that a lot with a ship grounding."

The Honduran-flagged Jireh freighter hit a reef off Mona Island in late June and alerted authorities, who in addition to cargo found more than 60 illegal Haitian migrants aboard the ship. Authorities have said the migrants reported they were headed to the French Caribbean island of St. Martin.

Roszkowski said he expects the freighter will be completely removed in upcoming weeks, but that unstable weather has slowed the process. He said the freighter's impact on nearby coral has been minimal, and that divers already have replanted some of the affected coral.

The plan is to tow the freighter 12 miles (19 kilometers) offshore and sink it in 6,000 feet (1,830 meters) of water after it has been thoroughly cleaned, he said.

"If there is any residual oil, it won't hit Mona Island," he said. "There will be some kind of a sheen coming off of it. There's nothing we can do about it."

He said investigators with the U.S. Coast Guard have not been able to locate the owner of the freighter, and that the cleanup is being paid for by an oil spill liability trust fund, not taxpayer dollars.

The Coast Guard originally said the ship measured 185 feet (56 meters).