Public rallies have become a rarity in oil-producing Azerbaijan, where police have twice in the past month prevented small unsanctioned protests by opponents of President Ilham Aliyev demanding the right to gather in public.
On Friday, Baku police rounded up dozens of people and bundled them into waiting buses when they assembled at Baku's State Oil Academy to commemorate the massacre of 12 people at the academy a year ago.
State-controlled media said some of those taking part in the commemoration were affiliated with opposition groups. A police spokesman said they did not have permission to gather.
Authorities regularly deny permission for public gatherings, under what rights groups say is a worsening crackdown on dissent and freedoms conducted under the cover of an oil-fueled economic boom.
"The authorities celebrate the Flower Festival every year, spending a lot of money to bring expensive and rare tulips to the country, but cannot commemorate those who died in the academy a year ago," said a student who gave his name as Rashad.
The Flower Festival on May 10 marks the birth of Azerbaijan's late long-serving leader Heydar Aliyev, who was succeeded as president by his son Ilham in 2003.
The motive behind the oil academy killings, which sent shock waves through the mainly Muslim country, remains unclear.
On April 30, 2009, police said a gunman entered the academy shortly after the bell for morning classes, and walked from floor to floor firing from a pistol. He shot dead 12 students and staff members before killing himself.
At the time, officials described the shooter as a mentally disturbed loner but have subsequently made four arrests.
On Monday, Azerbaijan's state prosecutor said the shooter, a Georgian citizen of Azeri origin, had been offered $50,000 by an Armenian from the same region in Georgia to carry out the massacre. An arrest warrant was issued for the Armenian.
Azerbaijan and Armenia are sworn enemies in the unresolved conflict over the breakaway mountain region of Nagorno-Karabakh.
