More than 700 Russian schools are set to close this year because of a slump in the number of children of school age, Russia's chief public health doctor said Wednesday.

Russia saw birth rates drop dramatically in the turbulent 1990s and its demographic situation has remained negative, with more deaths than births, ever since.

President Vladimir Putin last year urged Russians to have at least three children.

"We plan to close 733 schools this year," said the outspoken public health official Gennady Onishchenko, quoted by the Interfax news agency. "You understand the reason: there aren't enough children."

"For some reason we have forgotten why we came into the world and we came with only one aim: to create new life, to continue our line," said Onishchenko, who has three children.

Russia has more than 44,000 schools.

According to the state statistics agency, Russia saw 1.902 million births in 2012, up from 1.796 million in 2011, but there were still slightly more deaths than births.

A recent uptick in births is partly driven by a wave of immigrants from ex-Soviet states where larger families are the norm.

Russia has a population of 143.3 million. The state statistics agency has published a worst-case scenario showing that the population could fall to 130.8 million by 2030.