Police in Greece say four Russian tourists have died and 30 others injured when a bus overturned on a highway outside the northern city of Thessaloniki.

The bus skidded off the road during rainfall before dawn Friday, 15 kilometers (9.5 miles) east of the city, according to police. The tourists were being transported from a nearby resort to Thessaloniki airport, from where they were due to return to Russia on a charter flight to St. Petersburg.

Seventeen of the passengers on the bus were unharmed, while the driver was also among the injured.