Russian anti-fascist activist shot dead in Moscow

* Death follows arrests of ultra-nationalists

* 26-year-old campaigner died on spot

MOSCOW, Nov 17 (Reuters) - An anti-fascist campaigner was shot dead in Moscow, investigators said on Tuesday, in what a fellow activist said may have been revenge for the arrests of ultra-nationalists earlier this month.

A man opened fire on an "active member of the anti-fascist movement" on Monday evening in the Russian capital, state investigators said in a statement. He died on the spot.

Local media reports identified him as 26-year-old Ivan Khutorskoy.

"Various motives are being explored, including that he was murdered for his involvement in the anti-fascist movement," the investigative branch of the Prosecutor-General's Office said in a statement posted on their website,

Earlier in November, two ultra-nationalists were arrested for the murder of human rights lawyer Stanislav Markelov and opposition reporter Anastasia Baburova, who were gunned down in broad daylight near the Kremlin in January.

In 2006, Markelov represented the mother of an anti-fascist campaigner who he said was killed by neo-Nazis.

A fellow anti-fascist campaigner, speaking on condition of anonymity, told Reuters Monday's murder could be out of spite: "Ivan (Khutorskoy) knew Markelov. His murder was either revenge, or a challenge to the authorities following the arrests."

Leftist political website wrote: "For the majority of Ivan's friends, it's clear that his murder was carried out by Russian Nazis."

Russia suffers from a high number of street attacks on its migrant workers, mostly dark-skinned Muslims who come from former Soviet countries, that are widely blamed on neo-Nazis. (Reporting by Amie Ferris-Rotman; Editing by Charles Dick)