Polish police arrested a gay rights activist in central Warsaw on Friday, implementing a court order for two months' preventive detention that sparked angry scenes as dozens protested.
The activist, who was referred to officially in court as Mikhail Sz. but who identifies as a woman with the name Margo, is suspected of causing criminal damage to a van carrying homophobic slogans in Warsaw in June.
The activist is also accused of pushing a volunteer from the Pro-Right to Life Foundation which owned the van.
Margo was detained at the offices of Campaign Against Homophobia but dozens of protesters then managed to block the police car, prompting a short stand-off before officers cleared the way to allow the car to pass.
"The court ordered the detention of this person for a period of two months," Aleksandra Skrzyniarz, a spokeswoman for the prosecutor's office in Warsaw, was quoted as saying by the news channel TVN24.
The PAP news agency quoted Margo as saying before the arrest that it was a "repressive" measure.
Hanna-Gil Piatek, a leftist lawmaker who was at the scene of the arrest, said on Twitter: "I wish serious criminals were prosecuted as diligently as activists."
Margo belongs to a campaign group called Stop The Nonsense, which is also suspected of draping several Warsaw monuments, including a statue of Jesus Christ, with LGBT flags and anarchist symbols last week.
Prosecutors have charged three people in that case for desecrating monuments and hurting religious feelings.
The van from the Pro-Right to Life Foundation used to be a common sight in the centre of Warsaw, plastered with posters linking homosexuality to paedophilia.