Cuba began the 2017-2018 school year on Monday with 1.7 million registered students and two key challenges - updating the national education system and training more teachers to cover the instructor shortfall in several provinces.

Some 10,698 schools, 49 more than last year, opened their doors to elementary, high school and pre-university students, not to mention assorted other special schools, the Education Ministry said.

Universal free education is one of the hallmarks of the Cuban Revolution, although for a number of years the shortfall in the number of teachers and reportedly low quality of the offered classes have been the focus of attention on the island, where students make up about one-fifth of the population.

This year the authorities have focused on the third big improvement drive in the educational system, which will be implemented on an experimental basis in 154 schools throughout the country.

One of the aims of the process launched in 2010 is for the contents of the courses to progress in a linear, non-repetitive manner from elementary school through pre-university, adding additional studies with the objective of creating a "more open and participatory" educational model where the students receive the knowledge they need, Deputy Education Minister Margarita McPherson said.

The basic courses will be retained, she said, albeit with adjustments to the programs, with the high school natural sciences curriculum being separated into biology and geography, while computer studies, to date taught only in 7th grade, will be expanded to 8th and 9th grades.

Education Minister Ana Elsa Velazquez said that teacher coverage this year is guaranteed to be 93 percent, although the deficit in instructors in recent years persists in the provinces of Ciego de Avila, Havana, Matanzas, Artemisa and Mayabeque, though to a lesser degree than before.

She said that the priority is to strengthen teacher training at the high school level with the goal of training more than 1,000 new teachers this year in mathematics, physics, biology and chemistry.

In keeping with that objective, two new teacher training schools - one in the eastern city of Baracoa and another in Havana - will be opened, augmenting Cuba's 26 such institutions that turn out more than 20,000 teachers, although this figure is considered insufficient to fill the country's vacant teaching slots.

Some 246,000 students will be enrolled in higher education this year, 28,000 more than last year, and new plans reducing from five to four years the length of study will be implemented in 91 percent of the university degree programs.