Burnley have apologised for the "unacceptable behaviour" of some of their fans in their win at Sunderland.
Saturday's game was briefly halted during the first half because missiles were being thrown from the upper tier of the stand housing Burnley fans.
It is understood an eight-year-old child was injured.
The Clarets said an investigation into the incident is ongoing and "anyone caught throwing objects will be liable to a banning order".
Burnley said in a statement: "The club will not let the actions of any individuals spoil, affect, or jeopardise the enjoyment of all our supporters, who have been magnificent all season.