A group of pro-democracy advocates were attacked Tuesday by Cossack nationalists at an airport in southern Russia.

Alexei Navalny and his anti-corruption activists were set-upon by a large group of Cossacks who poured milk on the activists and then punched and kicked several of them. At least six activists, including Navalny, were injured.

Navalny's spokeswoman Kira Yarmysh said that roughly 30 members of Navalny's anti-corruption foundation had arrived at the Anapa airport Tuesday morning as part of a team-building exercise in the countryside when they were attacked by the Cossacks.

At the airport, which lies on the Black Sea coast, 900 miles (1,500 km) south of Moscow, the Cossacks yelled: "Get off our land!" before charging the group, beating up men and women. One activist was hospitalized, Yarmysh said.

Dmitry Slaboda, one of the Cossacks, said the original plan had been just to throw milk at Navalny and his supporters and to hurl insults at them, but that things had turned violent after one of them had elbowed an old Cossack to the ground.

"The fight broke out because of that blow," Slaboda told the Govorit Moskva radio station. "We just wanted to show them that there is no room here for Navalny who lives on American money."

Cossack assault on video

The video, however, did not capture the alleged blow against one of the Cossacks - wearing their traditional hats; some in military fatigue.

The police are investigating the incident, according to the Interfax news agency. But critics allege that such attacks have become almost commonplace outside of Moscow in recent years, saying that attackers often operate with impunity.

Navalny, 39, was traveling with his son when the attack occurred. In a series of tweets the anti-corruption advocate said the attack was premeditated and coordinated. He also said it was unfathomable that there would only be two police officers in the whole airport, especially in the south where the threat of a terrorist attack remains high.

Asked about the attack, Dmitry Peskov, a spokesman for the Kremlin, told reporters in Moscow: "I would not want to interpret it based on just one source...Was it really an attack? And if it was, who carried it out, who turned to the police later?"

The Kremlin frequently portrays the liberal opposition as a foreign-funded fifth column intent on sabotaging the country.

bik/msh (AP, Reuters)