Quoting eyewitnesses, Paraguay's Cerro Cora Sistema TV has described the assassination of Vice-President Luis Maria Argana.

"Argana's vehicle was circulating on Sargento Gauto Street heading towards Venezuela street. At the intersection, where drivers have to stop because there is a traffic bump, three people dressed in military gear - two of them armed with shotguns and a pistol - opened fire on Argana's car," a correspondent said.

"The chauffeur attempted to back up, and this is why the vehicle ended up in the position it is now. The chauffeur could not avoid the attack. The chauffeur was the first one to be shot and then the other passengers."

"The three assailants boarded a dark green Tempra car, which was later abandoned at 300 metres from the scene of the crime. After setting it afire, they boarded another vehicle, apparently a dark grey VW, in which they sped away.

"This is the concrete account we were able to obtain at the scene of the crime this morning."

The TV said a police bomb squad was trying to detonate the two hand grenades left by the assassins; one was next to Argana's van, and another one inside the van.

"The experts just detonated one of the hand grenades and this is why police asked neighbours and bystanders to evacuate the area."

"There is much confusion here among the people and the police forces themselves. There is a large deployment of police forces, Operation Humming Bird, which was meant to completely seal off the city of Asuncion, to conduct a major dragnet operation to hunt for the four suspects."