SOFIA, Bulgaria (AP) — A bomb exploded on a bus carrying Israeli youth in a Bulgarian resort Wednesday, killing at least six people and wounding 32, officials said. Israeli Prime Minister Benjamin Netanyahu called it "an Iranian terror attack" and promised a tough response.

The explosion took place in the Black Sea city of Burgas, some 400 kilometers (250 miles) east of the capital, Sofia. TV images showed smoke billowing from the scene — a parking lot at the local airport where the Israeli tourists had landed shortly before the blast. Several buses and cars were on fire near the shell of the exploded vehicle.

Israeli Foreign Minister Avigdor Lieberman, after being briefed by his Bulgarian counterpart, said the explosion was caused by a bomb placed on the bus. He said seven people died, but by Wednesday night the Bulgarian Foreign Ministry had placed the death toll at six and the number of wounded at 32 people.