NICOSIA — A home in Cyprus where police seized five tons of a chemical compound that can be turned into an explosive had been kept under surveillance for some time before officers moved in, a government official said June 3.

Authorities put the Larnaca home in their sights after being tipped off, Justice Minister Ionas Nicolaou told The Associated Press, without revealing the source.

Police are holding a 26-year-old Lebanese-Canadian man in connection with the seizure. He faces charges of conspiracy to commit a criminal offense and possession and transportation of explosives.

A security official told the AP that the suspect arrived in Cyprus on May 21st and that authorities are also searching for the man who owns the home, in connection with the case.

The official spoke on condition of anonymity because he isn’t authorized to discuss information involving security matters.

It’s unclear what use was intended for the cache of ammonium nitrate, which was stored in about 420 boxes.

The official said the suspect is denying the charges and isn’t cooperating with authorities, which are investigating whether he’s linked to Lebanon’s anti-Israeli group Hezbollah.

The suspect is due to appear in court June 4 for renewal of his detention order. In his first court appearance last week, the judge ordered the proceedings to be closed to the public after a request by the state prosecutor.

In 2013, a Cyprus court sentenced a Swedish-Lebanese man who admitted he was a Hezbollah member to four years in prison after finding him guilty of helping to plan attacks on Israelis in Cyprus. No Israelis were attacked.