Thousands of protesters gathered in Albania's capital for a sixth consecutive day on June 6 to oppose plans for a luxury resort linked to US investor Jared Kushner, arguing that the development threatens a protected coastal ecosystem and lacks transparency.

Demonstrators marched through central Tirana carrying banners reading "Albania Is Not for Sale" and demanding the resignation of Prime Minister Edi Rama, whose government has strongly backed the proposed project on the Adriatic coast.

The planned development, backed by Kushner's investment firm Affinity Partners and local partners, would be built near Zvërnec, a coastal zone known for its wetlands, flamingo populations, Mediterranean monk seals and sea turtle nesting sites.

The protests have intensified following a widening investigation into land ownership connected to the project. According to the Organised Crime and Corruption Reporting Project (OCCRP), Albanian anti-corruption prosecutors last week froze the bank accounts of Albania Land Development, a company linked to the resort, as part of an investigation into allegedly fraudulent property titles.

"The preventive seizure ... targeted Albania Land Development amid a widening investigation into allegedly fraudulent property titles," the OCCRP said.

Environmental groups and local residents say the project could damage one of Albania's most important coastal habitats. Public anger has also been fuelled by clashes between protesters and private security personnel guarding the site, footage of which circulated widely on social media.

Rama has defended the development, portraying it as a major opportunity for Albania's tourism industry while rejecting claims that construction is imminent.

"There is no project yet. There is no building permit yet. There is no construction yet. There is not even a final design yet," Rama wrote on social media on June 6.

"There is only a vision and a plan: to transform Albania into the most attractive destination for elite tourism in this part of the world, while simultaneously creating a positive net environmental development."

The prime minister said international experts in ecology, biodiversity and sustainable tourism were working on the concept and argued that current plans would increase green space and improve biodiversity indicators.

Rama also questioned media coverage of the protests, saying attendance had been exaggerated and describing some online discussion as "fabricated digital hysteria". He said turnout had ranged from about 2,000 participants to a peak of around 8,000.

Opponents of the project dispute those figures and accuse the government of prioritising luxury tourism over environmental protection and local communities.