For this year's edition, healthcare workers from the Navarre region were chosen for the launch of the traditional ceremony.

Standing on the third-floor balcony of the city hall building, Clint Jean Louis Fernández, deputy head of the city's Emergency department, and Araceli Sergio Aguilera, a nurse with the advanced life support ambulance service in Tafalla, took turns to deliver the famous opening words: "People of Pamplona, long live San Fermín!"

The packed square immediately erupted with cries of "Viva!" and "Gora!" as thousands of red neckerchiefs were raised into the air, coloured confetti fell and the rocket signalled the start of nine consecutive days of celebrations, which will continue until 14 July.

Warm conditions

The square had been full for hours before midday despite temperatures exceeding 25 degrees Celsius. Thousands of residents and visitors arrived early to secure a place for one of Spain's best-known festivals, with music, dancing and singing building anticipation as noon approached.

Warm weather accompanied the opening ceremony, with Spain's national weather agency, Aemet, recording 29 degrees nearby in Plaza Labrit.

However, as is customary during the chupinazo, many revellers cooled off by throwing wine, water, balloons and balls into the crowd. Within minutes, spotless white clothing had turned pink after being soaked in red wine.

After the rocket was launched, celebrations spread across the city, with thousands more watching the proceedings on six giant screens.

Around 50 municipal police officers helped clear a route for the traditional bands of bagpipers and txistularis, musicians who play the Basque txistu, a three-holed flute. They performed the traditional tune 'Ánimo pues' as crowds bounced in unison across the square.

The festival's distinctive white and red colours will remain on display until midnight on 14 July, when the traditional 'Pobre de mí' farewell song brings the celebrations to an end.