(Reuters) -Ecuadorean President Guillermo Lasso announced on Saturday a shake up of the high ranks of the security forces following the killing of seven inmates accused in the murder of presidential candidate Fernando Villavicencio.

He removed two officials, the prisons director and the head of the police investigations unit, and replaced the head of the national police with Cesar Augusto Zapata Correa, a long-time member of the force with nearly 35 years of experience.

The announcement came after six inmates were killed at the Litoral Penitentiary on Friday and another was killed in a Quito prison Saturday.

Another prisons official in charge of the prison where the six were killed was taken into custody for questioning, according to the president's announcement. Lasso also ordered the transfer of six inmates implicated in Villavicencio's murder for their security.

Violence, blamed by the government on drug gangs, has sharply increased in Ecuador in recent years and the latest killings seemed to underline rising lawlessness.

Ecuador's attorney general's office also launched an investigation into the country's prisons agency, the office said earlier on Saturday.

Prosecutors said they initiated the investigation because the agency, SNAI, did not carry out a pending order to transfer for security reasons the six inmates killed at the Litoral Penitentiary on Friday.

Villavicencio, a prominent journalist who exposed corruption and organized crime, was gunned down while leaving a campaign event in August. Police arrested six people that day and one suspect was killed. Another seven suspects were later arrested.

Lasso was meeting with his security cabinet on Saturday and canceled an upcoming trip to South Korea to "address the crisis in the penitentiary system," according to his official social media account. The government has previously promised to identify the intellectual authors of Villavicencio's murder.

Villavicencio built his career on exposing corruption by politicians and business leaders and before his death had denounced both the Albanian mafia and a leader of the Los Choneros gang who goes by his alias Fito.

The minister of the interior said Friday an investigative police report into Villavicencio's killing was ready. The report is not yet public.

The second round run-off vote will be held on Oct. 15.

Both candidates, business heir Daniel Noboa, who is narrowly leading polls, and leftist Luisa Gonzalez, have demanded the government clarify information about the prison killings.

The killings of the suspects are unlikely to affect voting intentions for the second round, political analyst Alfredo Espinosa said. However, clarity about who is responsible for Villavicencio's murder could, especially if a politician were to be found to be involved, lead to "an ethical and moral shakeup in the country," Espinosa said.

Ecuador removes, investigates security officials after killings of suspects in candidate assassination