Image copyright AFP Image caption Foreigners that do not hold permanent residency won't be allowed to attend Pink Dot this year

Singapore's Pink Dot LGBT rights rally will allow only Singaporean citizens and permanent residents to attend this year's event because of legal changes.

Organisers announced the restrictions with "profound regret", saying they had been reminded of new rules by police in the wealthy city state.

Previously only locals were allowed to actively "demonstrate" by holding up placards, but foreigners could nonetheless attend, Pink Dot says.

Gay sex is illegal in Singapore.

The Pink Dot rally has been held annually since 2009 in the country's Speakers' Corner, where demonstrations are allowed without a police permit. About 30% of Singapore's population are neither citizens nor permanent residents.

In a statement on Sunday, Pink Dot said that recent changes to Singapore's Public Order Act meant that "the law no longer distinguishes between participants and observers, and regards anyone who turns up to the Speakers' Corner in support of an event to be part of an assembly".

As a result, the organisers said they would have to check identity cards at this year's event on 1 July. The event says 28,000 people attended in 2015.

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On Saturday, Singapore police warned that only Singaporean citizens and permanent residents could participate in assemblies at Speakers' Corner that do not have a permit.

In a statement, the LGBT event's organisers said they had "been honoured by the strong support from friends from around the world who have unfailingly attended our events over the years, observing as their Singaporean friends make a stand for inclusion, diversity and the freedom to love".

They acknowledged the new restrictions could separate couples, friends and families, adding they were "just as upset by this".

Pink Dot warned that if non-Singaporeans or non-permanent residents insisted on attending the event, both they and the organisers could be charged and prosecuted.

Singapore's Ministry of Home Affairs said it was not trying to proscribe such events.

"This approach is consistent with the government's long-held position that foreigners and foreign entities should not engage in our domestic issues, especially political issues or controversial social issues," a spokesperson told the BBC.

The spokesperson said that the rules were "applied equally to all public assemblies and processions".

Human rights group Amnesty International said it was concerned that new powers would be used to "further curtail freedom of expression and peaceful assembly in a country where government critics and activists are already heavily controlled".

The new rules are the latest setback for Pink Dot, after the government last year barred foreign firms from sponsoring events at Speakers' Corner without a permit.

Google, Twitter and Facebook had been among foreign multinationals that had previously supported the event. Local companies have since stepped in as sponsors.