Saint Petersburg (AFP) - Russian police on Monday detained young activists protesting against the persecution of gay men in Chechnya at a May Day parade in Saint Petersburg, an AFP photographer witnessed.

Recent reports of a brutal crackdown on gay men in the mainly Muslim North Caucasus region led for a decade by strongman Ramzan Kadyrov have caused an international scandal.

Riot police in helmets detained young activists -- some holding rainbow flags -- and bundled them into police vans during Monday's parade in Saint Petersburg's historic centre.

Police detained 17 activists, according to local news site Fontanka.ru and OVD-Info, a site monitoring activist detentions.

"Some people who breached public order at the parade were detained," a police source confirmed to AFP, without giving details.

Several protesters lay on the ground covered with a Chechen flag while another threw earth on top of them to symbolise killings, Fontanka reported.

Some carried rainbow flags and shouted "Kadyrov to the Hague!" Fontanka reported, referring to the international criminal tribunal.

Ruling party lawmaker Vitaly Milonov, one of the chief proponents of a controversial 2013 law that bans "gay propaganda" for minors, shouted abuse at protesters, a video posted by Life News site showed.

In March, Novaya Gazeta opposition daily reported that Chechen authorities were imprisoning and torturing gay men in the conservative region where homosexuality is taboo and can be punished by killings by relatives.

A group of Chechen men in a safe house close to Moscow later confirmed to AFP that they had fled the region in fear of their lives.

Kadyrov rejected the "provocative" reports while meeting President Vladimir Putin last month.

Russia's Prosecutor-General's office said it had opened an inquiry but had not received any official complaints from victims.

Kremlin spokesman Dmitry Peskov downplayed the reports, saying there had been "no confirmation" of violence and arrests.

Rights activists protested in Berlin on Sunday ahead of a visit to Russia by German Chancellor Angela Merkel on Tuesday. She is due to meet Putin in the Black Sea city of Sochi.

photo-mak-am/cw