NANJING - A Chinese maritime court on Saturday ordered the detention of a South Korean cargo ship over a chemical spill that partially contaminated the drinking water source of a city downstream the Yangtze River in east Jiangsu province.

The Wuhan Maritime Court, which has the jurisdiction over the region, ordered to detain the cargo ship Gloria at Yangtze riverside city of Nantong and set a bail of 20.6 million yuan (3.3 million U.S. dollars), Bu Xiaofang, a spokesman of Zhenjiang municipal government, said late Saturday.

The government on Tuesday confirmed that phenol levels collected on February 3  in water samples in Zhenjiang were excessive, and the pollution caused tap water in some parts of the city to emit a pungent smell, sending panicked residents to stockpile bottled water from supermarkets.

An initial probe was conducted after authorities said they "highly suspect" a South Korea cargo ship that had docked at Zhenjiang spilled the chemical into the river.

"We have gathered evidence that the source of pollution was discharged from the pipe of Gloria," said Mao Desheng, deputy head of Zhenjiang's maritime bureau.

"I believe the cause of the spill will soon be verified and made public as the judicial procedure starts," he added.

Water samples of Zhenjiang and cities further downstream the Yangtze had not been detected with excessive phenol since February 4, officials said. The authorities have also ensured residents that the supply of purified bottled water is sufficient.

Phenol, also known as carbolic acid, is an organic compound that can irritate eyes and skin. Soluble in water, if absorbed in large amounts it can damage liver and kidney.

The Yangtze, spanning 3,219 km west to east across China, is the country's longest river. It disembogues into the East China Sea from Shanghai