On World Day Against Child Labor, Kerry said in Washington that more than 215 million children worldwide are involved in child labor and that the United States supports the grassroots level efforts by non-governmental organizations and others to combat the problem.
"We call on our partners in the international community to join us in fulfilling our collective commitment to these children by adopting national policies that eliminate child labor and create an environment that prevents the exploitation of children," he said.
At the Vatican, Pope Francis noted the exploitation of children often involves abuse and discrimination.
"It is a deplorable phenomenon, which is constantly increasing, especially in poor countries," the spiritual leader of the world's Roman Catholics said Wednesday..
"This is a real form of slavery. It is my heartfelt hope that the international community will initiate still more effective measures in addressing this authentic plague."
A UNICEF report released Wednesday said there are 150 million working children between the ages of 5 and 14.
An estimated 115 million children under 17 are employed in dangerous industries, often coming into contact with chemicals or carrying heavy loads.
UNICEF representatives said many children work to help their families but the practice becomes inappropriate when the work is dangerous or when children are missing school.
"When they are at risk and their health and well-being are impaired, they must be taken out of such situations," UNICEF Chief of Child Protection Susan Bissell said.
The International Labor Organization also released a report Wednesday. It stated that more than 71 percent of child laborers are girls.