Oil from a damaged tanker spread near Singapore’s north—east coast on Saturday, but efforts to keep the spill away from an island nature reserve were largely successful, authorities said.

The oil expanded along Changi beach on the north—east shores, prompting officials to close the area for water sports, the National Environment Agency said.

Oil patches spotted near a nature reserve on the northern island of Pulau Ubin had been largely cleaned up, the agency said, adding there were “no immediate signs of major damage” to the ecosystem.

“The oil containment boom set up earlier has helped to keep the oil spill out,” the agency said.

Local environmentalists were concerned that the oil spill could damage the island’s wildlife.

“These are areas with a high level of biodiversity,” said Louis Ng, executive director of the activist group Animal Concerns Research and Education Society.

Some species including crabs, starfish and clams were affected by the oil slick, Mr. Ng said.

On Tuesday, an estimated 2,500 tons of crude oil leaked from the Malaysian—registered tanker MT Bunga Kelana 3 after i collided with a bulk carrier in one of the world’s busiest shipping routes along the Singapore and Malacca straits.

The popular east coast beaches remained closed on the first weekend of Singapore’s month—long school holiday, with signs warning the public against water sports at the 7—kilometre—stretch.

But photos ran on Saturday by the Straits Times newspaper pictured anglers still casting their lines at the beaches and a man swimming.

The damaged tanker has been safely moved to a Malaysian anchorage in Johor province. There were no reports of injuries among the crew.

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