Billingham teenager Bella Culley is facing two years in prison in Georgia, South Caucasus.
Police used pepper spray to disperse demonstrators amid growing turmoil in the Caucasus country.
Salome Zourabichvili's term is due to end on Sunday, but she says she is her country's last legitimate institution.
Large crowds of protesters gather outside the Georgian parliament to object to the appointment of a new president.
The journalist told the Associated Press that the men took their equipment after the attack.
The prime minister had earlier vowed that the organisers of a week of pro-EU protests would face justice.
More than 300 people have been arrested and police are accused of using unnecessary force on the streets.
The ruling party denies any Russian link, but its actions raise questions about Georgia's path to the EU.
Demonstrations have been taking place for a fourth night in Tbilisi after Georgia's EU bid was suspended.
