The Vietnamese student, Vu An Tuan, was stabbed in October 2004 in St. Petersburg by a group of drunken teenagers on alleged race-hate motives.
"We deeply regret that the criminals who killed Vu An Tuan have not been named and have not received their due punishment yet," Le Dung said, commenting on Tuesday's jury verdict acquitting all the defendants of the murder, with nine found guilty of attacking other foreign nationals.
The diplomat said the murder profoundly worries both Vietnamese and Russians, and "goes against the traditionally good relations between our two nations." He also said his country has asked the Russian authorities to take urgent and effective measures to ensure the security of other Vietnamese nationals living in Russia.
Russia has experienced a wave of attacks on non-white foreigners this year, particularly in St. Petersburg, where an Indian student was stabbed to death and a Sudanese national attacked in September.
Other attacks in St. Petersburg in the past year have included the beating of a Chinese student, and the stabbing of a nine-year-old girl of mixed Russian-African origin in early 2006. A man from Mali was stabbed to death in the city in February, a student from Cameroon was murdered last December, and a Congolese student was killed in September 2005.
Routine attacks by skinheads and youth gangs on foreigners and people with non-Slavic features have also been reported in some other Russian cities.
A group of teenagers attacked a Vietnamese national, who lived in the town of Ostrogozhsk, in the Voronezh Region, on April 6 of this year. He was hospitalized and died of his injuries three days later.
