MADRID (AP) — Authorities in Barcelona evacuated one of the Spanish city's popular beaches Sunday after what is suspected to be a bomb dating from the Spanish Civil War was found in the sea.

Reports that an unidentified explosive device had been found at the Sant Sebastià triggered an alert, with police clearing and cordoning off a long stretch of beach in the early afternoon when it was full of people amid temperatures close to 30 C (86 F).

The device was discovered about 25 meters (80 feet) off the beach, lying in three meters (nearly 10 feet) of water, the city's security chief, Albert Batlle, told reporters.

It is 1.1 meters long and 80 centimeters wide, Batlle said, according to private news agency Europa Press.

He said the device is old and could date from the 1936-39 war but more details will be known only after Navy bomb disposal experts arrive Monday, he said.

Finding such decades-old explosive devices is not uncommon, he said.

The Navy team will explode the device, he said.