Chilean President Sebastian Pinera has rebuffed demands by students who have mounted mass protests for free university education, telling them "nothing is free in this life."

"We all want education, healthcare, and many more things for free, but I want to remind them that nothing is free in this life. Someone has to pay," said Pinera Thursday at the presidential palace, La Moneda.

The president said that "if we give free education to 10 percent of the most favored in society, what we would be doing is taxing all of society, including the poor, to finance the education for the lucky ones."

A free public education system for all has been the main demand of protesters who have taken to the streets in a series of mass demonstrations since Pinera announced plans two months ago to cut spending on education.

The protest movement, which has attracted widespread public support, has knocked Pinera's popularity to 26 percent.

Unions representing public workers and copper miners announced they would join the students, a sign of broadening opposition to Pinera, Chile's first conservative president since the end of the dictatorship of general Augusto Pinochet in 1990.

On Thursday, students demanded that police stop using tear gas to break up the demonstrations, while Pinera created an agency to establish minimum standards for schools.

The president also has proposed offering scholarships to the neediest students.