The Pride event in South Korea’s capital has been banned by police, but organisers have vowed to march regardless.
Police cited public safety and traffic concerns in their reasons for banning the parade, part of the Korea Queer Festival.
Conservative Christian groups had been vocal in their opposition to the festival, and organisers believe this is the real reason it has been banned.
Executive director Woo Ji-Young told AFP: “The police should protect the rights of free expression, rather than siding with those trying to suppress it.
“The parade will go on whether the police ban it or not.”
Around 20,000 people were expected to attend – and may be at risk of a fine or jail time, but Mr Woo said they are willing to take that risk.
It is not the first time pressure from conservative groups has harmed LGBT rights in South Korea. A human rights charter that would have offered protections to LGBT people was scrapped after anti-gay protests.
Schools in South Korea have also been banned from talking about LGBT issues.
The first lesbian kiss on South Korean television sparked complaints earlier this year.