UPDATE Thursday, 4pm: Police have arrested two people in connection with arson at homes in Spalding and Holbeach.
Although the incidents happened just 90 minutes apart early this morning, they are unconnected.
Detectives are this afternoon questioning a girl believed to be aged about 13 over the attack at Landsdowne Court in Spalding.
And a 20-year-old man is being held regarding the earlier incident in Albert Walk, Holbeach.
Thursday, 10am: House fires overnight in Spalding and Holbeach were arson.
One person had to be rescued from a three-storey house in Albert Walk, Holbeach, just before 1am this morning.
Crews from Holbeach, Spalding and Long Sutton helped to give first aid before the person was taken to hospital by ambulance.
The fire resulted in damage to a first floor living room and a garage.
It was extinguished using one hose reel and two sets of breathing apparatus.
Shortly after 2.35am this morning, three more crews were sent to Lansdowne Court in Spalding.
A spokesman for Lincolnshire Fire and Rescue said it resulted in severe fire damage to a sofa, curtains and a section of carpet.
There was also heat damage to a windowsill and frame, and smoke damage to the rest of the flat.
The fire was extinguished using one hose reel and two sets of breathing apparatus.