Three Czech tourists who were detained and charged with espionage in Zambia have returned home, the Czech Foreign Ministry said Sunday.

The three Czechs, who were arrested on October 12 after they were found taking pictures near military sites, could still be put on trial for an offence that carries a maximum sentence of 30 years in prison.

A ministry spokesman declined to give any details on the Czechs' return and said Prague had not received any information to suggest that the case was being dropped.

The ministry said in October that the three worked for a Dutch exhibition logistics company and had been visiting a friend in Zambia after a business trip to South Africa.

The pictures included one of a decommissioned military plane, along with No Entry signs outside another installation and the entrance to the presidential palace in the capital Lusaka.

(Reporting by Jason Hovet; Editing by Kevin Liffey)