Argentine singer Facundo Cabral, one of the stars of Latin American folk music, was shot dead in Guatemala City when unidentified gunmen riddled his car with bullets.
Cabral, who rose to fame in the 1970s as a protest singer, was killed along with his driver as they made their way to the city's airport before dawn, police said.
A spokesman for Guatemalan president Alvaro Colom said Cabral's vehicle was peppered with 18 bullets and Colom himself vowed to take swift action against the perpetrators.
Argentine television stations interrupted broadcasts with news of the 74-year old singer's death.
Mr Colom said he spoke to Argentine President Cristina Fernandez to offer his condolences for the killing, the motive for which was unclear.
A firefighter at the scene said colleagues saw black vehicles pull up and open fire on Cabral's white Range Rover and the beige Chevrolet Tahoe accompanying the singer.
Guatemala, one of the poorest countries in the region, has one of Latin America's highest murder rates.
Mr Colom has struggled to contain the violence and Cabral's murder is an embarrassment to the president just two months before a first round of presidential elections which polls show his centre-left National Union of Hope party (UNE) may lose.
The president's office said authorities were investigating whether the shooting was robbery-related or a targeted attack.
Enrique Vaca Narvaja, Argentina's consul to Guatemala, told Argentine television that Cabral's driver was a businessman named Henry Farina and it was unclear who was the target.
The second car, a security detail, was also sprayed with bullets, causing serious injury to at least one person.
Cabral's death sparked sorrow among his fans and Argentina's Foreign Minister Hector Timerman paid tribute to the singer on his Twitter account.
Rising from humble origins, the outspoken Cabral was best known for his 1970 song ‘No Soy De Aqui, Ni Soy De Alla,’ (I'm Not From Here, I'm Not From There Either) which was covered by many other artists including Julio Iglesias.
Cabral went into exile in Mexico during Argentina's 1976-1983 military dictatorship.
His songs later turned more spiritual and he continued to fill concert halls across Latin America. He had been in the Central American country on tour.
