A firework narrowly missed hitting a firefighter after it was launched at a fire engine which was attending a call.
The incident, on Saturday, happened after crews were called to deal with a motorcycle which was alight in Yarrow Road, Walderslade.
The firework was launched and exploded against the side of the engine causing a minor injury to the firefighter who had to be treated for shock.
In another incident in Chatham, a car was set on fire when a firework was launched at it at about 2000 GMT on Sunday.
New legislation
Police arrested two men, aged 23 and 21, for arson as a result of the attack on the Nissan Bluebird in Shipswrights Avenue in Chatham.
The most recent incidents follow a spate of attacks where fireworks have been used to blow up phone boxes and have destroyed cars.
Detective Inspector David Holmes, from Medway Police, said: "Our team of officers has worked very hard in recent weeks to identify what we believe to be the offending type of fireworks, but the fireworks concerned can be purchased legitimately by an adult making prosecution very difficult.
"I welcome the move to introduce new legislation next year that will enable us to deal with such situations much more effectively."