A man who entered a Swedish nuclear plant with explosives on him is currently in police custody and probably under interrogation, local authorities said on Wednesday.

The man was a welder who was about to perform a job at the Oskarshamn plant. He was stopped for a random security check and the security personnel found traces of explosives on him. They called police at about 7:58 a.m., said Sven-Erik Karlsson, spokesman for Kalmar County Police according to Reuters.

Karlsson also said that the man was carrying TATP (triacetone triperoxide) a high explosive which is very unstably, especially when exposed to heat. Considering the fact that the man was a welder the situation might have turned very explosive.

The man was taken at the Kalmar police station and the substance has been sealed off at the plant with a 300-metre perimeter, the police spokesman said.

Oskarshamn, a Swedish plant owned by Germany's E.ON and Finland's Fortum, released a statement on its Web site in which it said the reactor's safety was never threatened.

However, the man hasn’t been yet classified as a suspect in this case. Security personnel only found traces of the explosive substance in a bag he was carrying. The local police called bomb technicians from Malmo, the largest city in the area.

According to other media sources, the local police put two men under arrest for attempted sabotage.

"Two men who were taken in for questioning this morning have now been detained on suspicion of preparing for sabotage," Karlsson told Reuters.