A man has been detained amid an altercation after anti-racism protesters faced off against men wearing masks and draped in flags.

More than 100 people gathered in East Park for the Stand Up to Racism march in East Park, Southampton, at around 7pm.

The marchers, chanting 'racists off our streets', moved through Above Bar Street to Grosvenor Square where it had been touted an anti-immigration rally was due to be held.

READ MORE: Live updates as police keep protesters apart

Several men wearing England flags with their faces covered are in Grosvenor Square. Police have kept the two groups separate.

An altercation appears to have broken out with one man detained. 

A water bottle has been thrown at the group wearing England flags.