The number of children in Massachusetts’ foster care system has risen in recent months, prompting state officials to recruit more foster parents.

There were 6,118 children in the state Department of Children and Families foster care system at the end of July, about 9 percent more than the 5,618 a year earlier, according to the agency.

At least part of the increase has been attributed to the opioid crisis, which has led to more children being removed from drug-addicted parents, the Globe has reported.

The department has also been placing more children in foster care following a string of tragedies in recent years, including the case of Jeremiah Oliver, a Fitchburg boy who went missing in 2013 while under DCF supervision and was later found dead.

Statewide, the number of petitions filed by DCF to have children removed from their homes jumped by 38 percent, from 2,459 to 3,383, between 2011 and 2015, the Globe reported in May.

The influx of abused children also prompted the state to grant more “overcapacity waivers,’’ which generally allow more than four foster children in a single home.

Officials say efforts to bring more foster parents into the mix, including several large-scale recruitment events this past spring, have paid off. There were 4,793 foster homes as of the end of July, an increase of 11 percent, since November 2015.

The department is also bolstering foster parent recruitment staff in its field offices and recently hired two more statewide recruitment coordinators and a new assistant commissioner for foster care, adoption, and adolescent services.

The department’s goal is to “build a large, diverse community of foster parents so there are always safe homes for children in the cities and towns where they live and go to school,’’ the department said.

“DCF foster parents are true heroes, opening their hearts and their homes to children enduring the most traumatic of life circumstances,’’ DCF Commissioner Linda S. Spears said in a statement in May, when the department was announcing recruitment efforts. “They provide them with a nurturing environment, where they are safe and can begin to heal.’’

Matt Rocheleau can be reached at matthew.rocheleau@globe.com. Follow him on Twitter @mrochele