Sniffer dogs and mechanical diggers worked through the rubble in devastated cities in Ecuador on Wednesday four days after a powerful earthquake hit.

Hopes of finding more victims alive were fading fast.

Saturday's 7.8-magnitude earthquake struck the coast in the Andean country, killing more than 525 people and injuring about 4,600 others. It was Ecuador's worst quake in nearly 40 years.

President Rafael Correa said 54 people had been rescued alive from the fallen debris on Tuesday.

However, rescue workers scrambled to find survivors in the cities of Manta, Portoviejo, and Pedernales, which was almost completely destroyed. The defence department said more than 200 people were still missing. 

A magnitude 6.2 aftershock also struck again off the coast on Wednesday.

In the lesser hit southern city of Guayaquil, people resumed their daily routines as they warily manoeuvred in the streets. In the Plaza San Francisco, a square dating to 1702, a 25-storey high-rise was visibly leaning.

"I didn't notice it at first, because I was looking at it from the wrong side, but it's leaning away from us," Diana Gonzales, who works across the street, told Al Jazeera. "I'm ready to leave."

Gustavo Zuniga, president of the Association for Guayaquil's Security, a branch of the mayor's office, told Al Jazeera five buildings were completely destroyed, with more than 60 damaged.

Ecuador struggles to clean up after deadly earthquake

Source: Al Jazeera and agencies