Arsonists set fire to a lorry in the early hours of this morning (Tuesday).
Cambridgeshire Fire and Rescue Service crews from Huntingdon, Ramsey and Papworth were called at about 4.30am to a blaze on the A14 near Ellington.
A spokesman for the fire service said: "Crews arrived to find a lorry cab well alight. Wearing breathing apparatus, firefighters used three hose reels to extinguish the fire before returning to their stations by 6.15am."
In a separate incident, firefighters from St Neots were called at about 11.45pm on Monday to Hawthorn Road, amid reports of a car fire.
Firefighters extinguished the blaze and returned to their station by about 12.50am.
Investigations determined the cause of both fires to be deliberate
Anyone with information regarding either incident should contact police by visiting www.cambs.police.uk to submit an online report or call Crimestoppers, anonymously, on 0800 555111.