BEIJING -- China will integrate migrant workers into cities in an orderly way over the next five years, Chinese Premier Li Keqiang said Monday.

The government will improve the urban residence permit system to help the integration, ensure stable employment and safeguard the rights and interests of migrant workers, Li said in a letter to a ceremony held to honor migrant workers.

Li said migrant workers are a major force for China's modernization and have made great contributions to economic and social development.

Given decades of economic advance, China's urban areas have been expanding rapidly with an enormous population of migrant workers swarming into cities, most of whom, although working and living there, have no urban household registration which can grant them equal public services to other residents.

By 2014, the number of migrant workers amounted to 273.95 million, accounting for 20 percent of the country's population.

The difficulty for migrant workers to fit in cities has become a major barrier in China's human-centered urbanization and the government has prioritized the problem in its to-do list.

A top-level urban work conference held in the end of 2015 agreed that China's urbanization drive will focus on the integration of rural residents into urban areas. The government also plans to grant 100 million rural migrants urban household registration by 2020.

Local authorities were asked to help rural workers find jobs or set up businesses, provide necessary training, improve education and housing benefits to them and their children and include more of them in the social security system.