"Our deepest sympathies and solidarity to the British people, the victims and families of the #Manchester attack," Costa said in a message in English on his Twitter account, following a similar message in Portuguese.

Meanwhile, Portuguese officials said that there was so far no indication that any citizen of the country is among the victims of the bomb attack on Monday night outside a pop concert in Manchester, which claimed 22 lives and left many more injured. The Ministry of Foreign Affairs has been monitoring the situation since news broke, given that there are hundreds of thousands of Portuguese living in the UK.

The commander of Greater Manchester police, Ian Hopkins, on Tuesday announced an increased death tally of 22, adding that 59 people are being treated in eight different hospitals in the region.

He said that police believe one man only was involved in the attack, and that he was carrying an improvised explosive devices that he himself detonated. He is believed to have died in the explosion.

The attack took place at the venue where a concert by US pop singer Ariana Grande was performing. Her fan based is mainly composed of teenagers and children.