A demonstrator throws a tear gas canister back at riot police during a protest at the National University as a national strike continues in Bogota, Colombia November 26, 2019. Photo: REUTERS/Luisa Gonzalez.

Bogota - Violent protests erupted in Colombia on Tuesday ahead of nationwide marches that have been called for the second time in the space of a week.

Thousands of people in Bogota and other cities demonstrated against economic reforms and the death on Monday of young protester Dilan Cruz, who was shot in the head by police during clashes on Saturday.

Masked demonstrators clashed with security forces in Bogota and in the city of Neiva, where a police officer was seriously injured, broadcaster Caracol reported.

Protesters blocked several streets in Bogota, preventing bus traffic and forcing residents to walk home.

The demonstrators are demanding the cancellation of planned tax and other economic reforms, the end of killings of community leaders by armed groups and the dismantling of the riot police Esmad, which they accuse of brutal repression.

The South American country has seen six days of protests after an estimated 250,000 people attended nationwide anti-government marches on Thursday. Most of the rallies have been peaceful, but some of them escalated into clashes with police, looting and acts of vandalism. Four people have been killed.

Duque on Tuesday failed to make progress in talks with the National Strike Committee, which called the protests and includes trade unions and civil society organizations.

The committee refused to join a "national dialogue" that the president has called with political and economic players, and demanded exclusive talks with the government.

Duque on Tuesday announced changes to an upcoming tax reform, including value added tax relief for low earners and reduced health insurance payments for retired people on small pensions. But the National Strike Committee wants the government to scrap the entire reform.

Its 13 demands also include cancelling alleged plans for labour and pension reforms, agreeing to not privatize state companies, completing the implementation of the 2016 peace deal with the former guerrilla group FARC, and measures to protect the environment.

Protesters were due to start marching nationwide on Wednesday morning.

With the violent protests, Colombia joined a wave of civil unrest in South America that has swept Ecuador, Chile and Bolivia.

dpa