LIMA, Jan. 3 -- Peruvian President Pedro Pablo Kuczynski on Wednesday called for the immediate expansion of a key highway, the Panamericana Norte, a day after a tragic bus accident claimed the lives of at least 51 people.

"Today I have instructed the MTC (Ministry of Transport and Communications) to immediately begin an agreement with NorVial (the concession that operates the roadway) to expand the existing highway to three lanes on each side," Kuczynski posted to Twitter.

The Panamericana Norte is an alternate route to the one taken by the bus, which collided into an oncoming truck on Tuesday and plummeted off a steep cliff about 48 kilometers north of the capital Lima.

The accident occurred around midday at a dangerous turn in the road known as the "Devil's Curve."

Peruvian Minister of Transport and Communications, Bruno Giuffra, said passenger buses would be barred from that stretch of highway starting Wednesday, and instructed to use the alternate route.

Meanwhile, rescue efforts resumed Wednesday morning to recover bodies still trapped in the wreckage of the bus, which landed upside down on rocky shoreline some 100 meters below.

The Ministry of Health revised the death toll to 51, after using a drone to scan the crash site closely.

Authorities are still investigating the cause of the accident, but preliminary reports indicate the trailer truck had invaded the wrong lane.