Emergency services have been called to St Paul’s Road to an unknown incident.
One eyewitness, who wished to remain anonymous says that the police have been at the property all day, with ambulance and fire crews arriving in the last hour.
Video footage shows police carrying brown bags full of evidence to their cars.
People warned not to go to popular beach this weekend unless they have booking
Emergency crews battling to save someone’s life on Southsea seafront
Royal Navy warship based in Portsmouth is due to set sail on a three-year mission to maintain the security in Gulf
River Ems crisis: Westbourne villagers plead with Portsmouth Water to introduce a hosepipe ban
Southsea seafront incident: Police update after man found 'unresponsive'
A spokesman from Southsea Fire Station said: ‘We were on the scene assisting with the police incident.
‘We were assisting them with their personnel – but it is a police incident and they and primarily the ones dealing with it.’
More to follow.