Police have cordoned off a stretch of Hyde Road, in Gillingham, Dorset, and Army personnel and vehicles were pictured entering the cordon on social media.
This follows an incident in Salisbury in which a former Russian spy and daughter where poisoned using a nerve agent.
An recovery vehicle could be seen inside the area.
Fans will be allowed to attend Swindon Town's match at Gillingham this Saturday.
Medway Council had banned supporters from the League Two match because of a dispute over policing costs.
Tickets for Swindon's game against Gillingham have gone on sale at the County Ground - even though the match could be played behind closed doors.
Gillingham are in a dispute over policing costs but Swindon say they'll refund tickets if it can't be resolved. Full details on the club website.