The shooting occurred Saturday night near the Camp Springs and Morningside areas of Prince George's County, officials said. Roughly 12 people were in attendance at the 2-year-old's birthday party when someone started shooting.
Three of the seven people who were shot — all between the ages of 18 and 20 — remained critically injured, but Prince George's County Police Chief Henry Stawinski said they were all expected to survive.
The suspect remained at large as of 7:30 a.m. Sunday morning. Further information about the incident was not immediately clear, but Stawinski said a fight might have broken out before the suspect began shooting.
The Associated Press contributed to this report.