African countries should upgrade critical amenities like housing, education, clean water and health in the continent's intermediary cities and enable them act as buffers against uncontrolled rural-urban migration, senior officials from a pan-African lender said on Wednesday.

Babati Mokgethi, senior urban development officer at the African Development Bank (AfDB) said the solution to population explosion, crime, poverty and pollution in the continent's large metropolises lied in revamping intermediary cities.

"It is crucial to redirect a huge chunk of rural population in Africa to intermediary cities in order to reduce pressure on the big cities," Mokgethi said on the sidelines of the Africities summit underway in Kenya's western city of Kisumu.

Mokgethi said that investing in medium-sized cities will boost economic vitality in Africa's rural hinterland while acting as a holding ground for skilled workforce that migrate to metropolises in search for elusive jobs.

He said that intermediary cities that are currently home to about 15 percent of Africa's populations required modern transport infrastructure, reliable water supply and affordable housing for them to thrive.

Nnenna Nwabufo, managing director for East Africa at AfDB, said that by absorbing the bulk of Africa's rural population, intermediary cities could shield the continent from unsustainable urbanization.

Nwabufo said African governments should come up with innovative financing, legislative and policy tools to enhance sustainable growth of intermediary cities and leverage them to help tackle poverty, unemployment and ecological degradation.

According to Nwabufo, the intermediary cities were key to the vitality of Africa's agro-processing sector, indigenous manufacturing, cross-border trade and skills transfer.

She called for investments in essential services like clean energy, safe drinking water, health, sanitation and fiber optic cable in order to attract investments in the intermediary cities.

Kenya is hosting the ninth edition of Africities summit under the theme of "The Role of Intermediary Cities of Africa in the Implementation of Agenda 2030 of the United Nations and the African Union Agenda 2063."

More than 4,000 delegates, including former heads of state and government, ministers, mayors, investors and campaigners, are expected to come up with new strategies for hastening urban renewal in the continent.