MANILA, Philippines -- Fewer children are being drafted into the Philippines labor force, but keeping them in school remains a major challenge, a UN official said Thursday.

The number of Filipino children aged between five and 14 who are in the labor force has fallen from 913,000 in 2003 to 774,000 in 2005, said Keiko Niimi, a regional official of the UN's International Labor Organization.

"Despite all efforts, the fight against child labor remains a challenge," she said during a ceremony in Manila to mark World Day Against Child Labor.

"We have to ensure that child laborers are successfully integrated in schools and that they do not return to work until they grow up and acquire education and training," she said.

While the figures signal improvement, Niimi cited troubling education department data that showed the school participation rate dropping to a seven-year low of 38.22 percent in the 2006-2007 school year.

The poor must often choose whether to educate their children or send them to work to help support the family, she said.

In some cases, children attending schools must walk long distances, lack quality instruction and study materials, and often have to study in poor physical facilities.

Teachers may receive little support, training or poor salaries, while parents cannot always afford to pay for textbooks and uniforms as well as other school fees, she said.

"When families have limited resources, children as young as five are forced to work at the cost of dropping out of school, risking their health or even their lives," Niimi said.

Labor Secretary Marianito Roque said the government will implement a four-year project to raise school enrolment levels in areas of the country that have a high incidence of child labor.