Pope Francis has launched an appeal against child labor, calling it an "deplorable phenomenon" during his Wednesday general audience.

"It is my heartfelt hope that the international community will initiate still more effective measures in addressing this authentic plague," said Pope Francis on June 12.

"Listen, it is a deplorable phenomenon which is constantly increasing, especially in poor countries," he told thousands gathered in Saint Peter's Square.

He made his comments on the World Day Against Child Labor, a day created by the United Nation's International Labor Organization.

The organization states in its "decent work agenda" that it has "gender equality as a crosscutting objective."

But the organization's report released June 12 focused more on domestic work for children than on illegal employment of children.

The report stated around 10.5 million children worldwide work in homes and some have conditions "similar to slavery."

Pope Francis exclaimed, "woe to those who stifle them in their joyful enthusiasm of hope!"

"A serene childhood allows children to look with confidence towards life and tomorrow," the Pope said on a hot, sunny day in Rome.

"All children must be able to play, study, pray and grow, in their families, this in a harmonic context, in love and serenity, but these people instead of playing are slaves, and this is a plague," he affirmed.

The pontiff also stated, "this is their right and our duty."

"There are millions of children, mostly girls, who are victims of this hidden form of exploitation that often involves abuse, mistreatment and discrimination," Pope Francis said.

The organization created the World Day Against Child Labor in 2002 to prevent child labor "in economic and military fields."

Its report added that over half of the children involved in domestic work are aged five to 14 and over 71 percent are girls, many of whom endure physical or sexual violence.