ATHENS (Reuters) - Hundreds of demonstrators on Saturday paraded the coffin in central Athens of a Pakistani immigrant who was stabbed to death earlier this week, praying and opening the casket to show his face in protest at racist attacks in the country.

About 3,000 immigrants and human rights activists later gathered in the city's central Omonia square to demonstrate against racism, holding banners reading "Neo-Nazis out" and "Punishment for the fascist murderers of Shehzad Luqman".

The 27-year-old Pakistani was stabbed to death by two men on a motorcycle as he rode his bicycle to work in an Athens suburb in the early hours of Wednesday, in an attack police say may have been racially motivated.

"Perhaps his murder will bring hope that these attacks will stop. We are protesting for the government to take measures to stop racist attacks," Javied Aslam, head of the Pakistani Community organisation told Reuters, as about 300 Pakistani immigrants gathered outside city hall with the coffin.

Greece is a gateway for mostly Asian and African migrants trying to enter the European Union through its porous sea and land borders each year. They face rising hostility during the country's worst economic downturn in six decades.

A police official told Reuters earlier this week a 25-year-old and a 29-year-old firefighter had admitted to stabbing Luqman in the chest following a drunken argument.

Police discovered dozens of pamphlets of the ultra-nationalist Golden Dawn party in the home of one of the attackers.

Golden Dawn, which says it wants to rid Greece of illegal immigrants, won 7 percent of the vote in parliamentary elections last June, entering the assembly for the first time on its fiercely anti-immigrant agenda.

Recent opinion polls show it ranks third among Greek political parties, with support at 10.7 to 12 percent.

The U.N. refugee agency, UNHCR, says racist attacks have risen to alarming levels during the crisis, which has made more than one in four Greeks unemployed and eroded living standards, with authorities doing little to tackle the problem.

Rights groups say most victims are attacked in public spaces such as squares or on public transport, usually by groups of men dressed in black and at times with their faces covered.

Amnesty International said Luqman's killing was not an isolated incident but showed a "continuing failure" of the Greek authorities to take action to put an end to racist violence.

(Writing by George Georgiopoulos; Editing by Sophie Hares)