LJUBLJANA, Slovenia — A reactor at Slovenia's only nuclear power plant was shut down Wednesday after a water leak, but the country's nuclear watchdog said there was no danger to people or the environment.

Slovene authorities reported that the Krsko power plant had been completely shut down, the European Union's executive body said. Parts of the reactor were still cooling down and there appeared to be no discharge, the EU statement said.

The European Commission said Slovene authorities had reported that a loss of coolant occurred in the plant's primary cooling system.

Slovenia's Nuclear Safety Administration said the reactor was being shut down as a precaution so that technicians could inspect the cause of the problem.

"The event did not affect employees, the nearby population or the environment," a statement said.

The International Atomic Energy Agency, which monitors nuclear accidents, said in a statement that its Incident and Emergency Center "is gathering information and there will be a better assessment when we have facts in our hand."

The Krsko nuclear power plant in southwestern Slovenia has been in operation for about 20 years, according to its Web site. The facility generates about 5 billion kilowatts of electricity a year, or roughly 40 percent of Slovenia's energy needs, its operators said.