At least 181 people have been confirmed dead, with the cities of Cali and Pereira among the worst affected. Nearly 2,600 people have been injured and almost 200 remain missing, according to President Abelardo de la Espriella.
The earthquake struck at 7:34am local time on Monday and was felt across a wide area of western Colombia. More than 70 aftershocks have been recorded since the main quake, including two measuring 3.6 magnitude early on Tuesday.
The Colombian government has declared a state of emergency as rescue operations continue.
President de la Espriella, speaking from Pereira, said more than 1,100 homes had been destroyed and another 8,000 damaged.
In Cali, where 95 deaths have been reported, authorities have established a unified command centre to coordinate rescue operations. Mayor Alejandro Eder said 239 people remained trapped, while 949 had been injured and 45 buildings had either completely or partially collapsed.
Several upper floors of a hospital in Cali also collapsed, trapping some patients, including children.
In the northern Calima neighbourhood, four children were killed after part of the Gimnasio Calima school collapsed. Around 30 children were taken to medical facilities, some with serious injuries.
Authorities have imposed a night-time curfew in the area to prevent looting and maintain security.
Pereira has also suffered extensive damage, with 79 deaths reported by the city's fire department. Authorities declared a car-free day to allow emergency teams and volunteers to move more easily through the city as search operations continue.
Video footage from Pereira showed hundreds of rescuers and volunteers clearing debris from collapsed structures in an effort to reach people trapped underneath.
In Manizales, five people have died and around 60 buildings have reportedly collapsed either partially or completely.
Mayor Jorge Eduardo Rojas warned residents to remain cautious because of continuing aftershocks. He also urged people not to circulate unverified messages or social media posts that could cause further panic.
The earthquake has triggered an international response. The United Nations expressed solidarity with the Colombian people and said it was supporting the government's emergency response.
Spain's Foreign Minister José Manuel Albares said 164 Spanish nationals remained unaccounted for, although there were no reports of Spanish citizens being killed or injured.
The United States has announced $15.5 million in aid for Colombia, while Ecuador, Brazil, El Salvador and Venezuela have also offered assistance.
With hundreds of people still missing and further tremors continuing, rescue workers are facing a critical race against time to reach survivors beneath the rubble.
