Monday’s attack was reportedly carried out by 22-year-old Manchester local, Salman Abedi, who detonated an improvised explosive device among the crowd as the concert came to a close.

Grande has a large following of teenage girls and children, and many minors were among the casualties.

The youngest victim to date is eight-year-old Saffie Rose Roussos, who died after being separated from her family as the attack unfolded.

Foreign Minister Angelino Alfano has shown solidarity with Britain following the attack.

"Condolences and pain for what happened in Manchester," Alfano said.

"We are close to the British people, to the government, to the injured and to the families of the victims."

Former prime minister and head of the Democratic Party (PD), Matteo Renzi, took to social media to express his condolences.

"Sowing death in a concert among the young, where music should hold sway: what happened in Manchester breaks my heart. Prayers and thoughts for the victims and their families, devastated by pain that begins today and will never end," Renzi wrote on Facebook.

The lights of many historical sites in Rome, including the Colosseum, the Trevi Fountain and Piazza del Campidoglio, were turned off at midnight in solidarity with the victims of the attack.

The replica statue of Michelangelo's David in Florence's Piazza della Signoria carried a Union Jack in its hand in sympathy with Manchester, while a black arm band was placed on its arm as a symbol of mourning.

Gentiloni stated that there is currently no evidence to suggest that any Italians were involved in the tragic incident, and that the foreign ministry is working closely with British authorities to learn more.

The premier added that Italy's security forces were doing everything possible to combat terrorism and keep Italians safe.

Security has been raised across Italy in the wake of the Manchester attack, especially in the lead up to major events including the MTV Awards in Piazza del Popolo on Saturday night, the Roma-Genoa game at the Stadio Olimpico on Sunday, the June 2 Republic Day holiday and a Pentecostal event featuring Pope Francis at the Circus Maximus.

Security will also be tightened for the G7 summit in which high profile international leaders will meet in Taormina, Sicily.

With ANSA