BELGRADE, Serbia (AP) — Serbian authorities say they have discovered some 25 tons of highly toxic waste illegally stored in barrels and containers buried in the ground at a private property southwest of the capital, Belgrade.

The government's ecology ministry said in a statement on Friday that tests are underway to determine whether the waste has contaminated soil and wells in the Obrenovac municipality, some 30 kilometers (18 miles) from Belgrade.

Authorities say toxic chemicals include benzene and that further analysis is being conducted. They have warned residents not to use water from the wells.

Police have detained the owner of the property who faces charges of endangering public safety.

Serbia is heavily polluted due to years of mismanagement and economic decline. The Balkan country is seeking to join the European Union.