Millions of Christians around the world are expected to unite in prayer this weekend for vulnerable children.
The World Weekend of Prayer is an initiative of Viva, an international charity serving at-risk children, and is now in its fifteenth year.
Viva hopes to top the success of last year's event, when more than two million people took part.
The weekend is part of its wider work to raise awareness of the plight of children who are in situations of suffering.
"The point of the weekend is to put the focus back onto the child, praying both for and with children," said Viva's chief executive Patrick McDonald. "We need to call out to God on behalf of those without families, without homes, without education, without a hope for the future. And there are many ways in which we can do that."
Some churches in the United Kingdom are marking the weekend by making the plight of children a focus for their Sunday services and hosting child-friendly interactive prayer times.
In Kampala, Uganda, hundreds of children are taking part in a prayer march through the city to raise awareness about child rights.
Viva has spent the last few months mobilizing more people in praying for children. Its "Got a minute?" campaign asks adults to commit to spending just 60 seconds in their day praying for vulnerable children around the world.
McDonald hopes the prayers will add up and bring about a lasting change for children.
"If every person involved takes a minute to pray, just one minute out of a whole weekend, that could mean two million minutes – that's equal to more than three and a half year's worth of prayer devoted to children at risk," he said. "When we stand together and pray with one voice not only will our world sit up and take notice, but I believe our God will hear and respond.
"Our prayers over this weekend really do have the power to bring about change in the lives of thousands of vulnerable children. So get involved, stand with us – every prayer counts!"