Vietnam has several hundred prisoners sitting on death row past their scheduled executions because the European Union is blocking the export of chemicals used for lethal injection, state media said Thursday.

The embargo is part of an EU effort to pressure Vietnam into abolishing capital punishment, deputy parliament speaker Huynh Ngoc told the official Communist Party daily.

Publication of the comments coincided with a visit to Vietnam by EU President Herman Van Rompuy, who on Wednesday urged the government in Hanoi to keep its promises to respect human rights.

Vietnam adopted lethal injection in July 2011, abandoning its traditional method of execution by firing squad.

Since then, however, not a single convict has been executed due to Vietnam's inability to obtain the necessary drugs.

Some Vietnamese lawmakers objected to doing away with the firing squad, which they saw as a powerful deterrent to crime. EFE