A Guatemalan opposition party filed a formal criminal complaint Tuesday against President Otto Perez Molina and other top officials for the deaths of eight protesters at the hands of the army.

Last Thursday's killings in the western province of Totonicapan amounted to extrajudicial executions, Democratic Liberty party lawmaker Edgar Ajcip said.

He said that his party, which assembled witness accounts of the incident, wants the people who ordered troops to the scene held accountable, not just the soldiers who fired the fatal shots.

Hundreds of people mobilized early last Thursday to block the Interamerican highway at six different points in Totonicapan province.

The protest was spurred by Perez Molina's proposals for constitutional changes, an overhaul of the curriculum for aspiring teachers and a recent hike in electric rates.

Two truckloads of army troops were sent to the spot known as Alaska to assist police trying to clear the highway.

Perez Molina - a retired army general - and his administration insisted for nearly 24 hours after the shootings that the troops at the scene did not fire their weapons, despite widely circulated images of a soldier pointing a rifle at the protesters.

Acknowledging the involvement of troops in the violence, the president said last Friday that the trouble started when a private security guard traveling on a cargo truck fired his gun in an attempt to clear a path through the crowd.

The security guard and the seven soldiers who fired shots were placed at the disposition of prosecutors.

Guatemala's deputy defense minister, Gen. Edwin Efrain Najera, told a congressional hearing on Monday that the troops used their weapons because they were attacked by the protesters.

"They had to take the shots to defend themselves," he said.

More than 30 other people were injured in the confrontation, including eight soldiers and around two-dozen civilians who received gunshot wounds. EFE