Palestine Action protesters have clashed with police in Trafalgar Square after they were banned from protesting outside Parliament.

On Sunday evening the Metropolitan Police imposed an exclusion zone around Parliament, with protesters facing arrest if they enter the area.

Palestine Action has responded by moving the protest to Trafalgar Square, outside the exclusion zone. It announced the change on social media and said: “The Metropolitan Police are trying to deter support from Palestine Action by banning the protest from taking place at the Houses of Parliament. Don’t let them win!”

Around 500 protesters, some wearing black face coverings and waving Palestine flags, gathered in a small area at the south of Trafalgar Square.

The protest momentarily descended into chaos as police officers burst into the crowd and detained two demonstrators.

After dragging the men out of the main group they were encircled by chanting crowds shouting “terrorists” and “we are all Palestine Action”.

Placards could be seen with the slogan: “Britain, US, Israel are terrorists… Hands off Palestine Action. Freedom for Palestine. Defend protest rights. Others read: “Defend the right to protest. Drop the charges.”

It comes as Yvette Cooper, the Home Secretary, is expected to announce plans to proscribe Palestine Action as a terrorist organisation after activists from the group damaged two planes at RAF Brize Norton, at a potential cost of millions of pounds.