The most senior Democrat on the US House Judiciary Committee has widened his investigation into Jared Kushner's business interests to include the disputed Albanian land where his investment firm plans to build a luxury resort.

The Albania investigation centres on land in a protected area near Zvernec, where Kushner's firm proposed the resort, a project that has sparked daily protests that have persisted for weeks.

Jamie Raskin, the committee's ranking member, wrote to Kushner on August 24 and published the letter a day later, demanding records and communications concerning his dealings with the Albanian government, the US government and the proposed real estate project.

Raskin, who represents Democrats on the Republican-controlled committee, asked for documents relating to real estate and business transactions in Albania, protests against Kushner-linked projects and any government involvement in the approval, financing or consideration of Albanian developments.

He also asked for information on the planned resort on the Albanian coast and whether Kushner or entities linked to him had received benefits from Albanian authorities.

The committee is examining whether the conduct could warrant scrutiny under the Foreign Corrupt Practices Act and whether federal rules covering bribery, conflicts of interest, foreign agents and special government employees need to be strengthened, Raskin said.

The letter does not carry subpoena power. Raskin is in the minority on the committee, whose chairman is Republican Jim Jordan, and the letter was copied to Jordan rather than issued jointly with him. But it establishes a formal congressional record of the concerns raised by Democrats and puts pressure on Kushner to respond.

Raskin said he had first contacted Kushner in April over what he described as conflicts created by his simultaneous role in private investment and involvement in US foreign policy.

"From the standpoint of the American people, your decision to act simultaneously in these two roles - one public for the government and one private for personal profit - has created a glaring and incurable conflict of interest," Raskin wrote in his April letter, pointing to the fact that 97% of Affinity Partners' funds came from foreign government sovereign funds, related commercial entities and foreign nationals.

Neither Kushner nor Affinity Partners responded, according to Raskin. Committee staff also contacted the firm's chief legal and compliance officer, Ian Brekke, on May 7 but received no response.

Raskin's latest letter says the committee's concerns have since expanded following developments in Albania.

"You may have been too busy causing a new foreign policy fiasco in Albania after your yachting foray in the Adriatic to get back to us," he wrote.

Kushner, President Donald Trump's son-in-law, continues to run Affinity Partners while also participating in diplomatic efforts involving international conflicts. That combination has drawn scrutiny because the investment firm has substantial foreign-backed funding and investments.

Kushner acquired the site for more than $120mn from Albanian businessman Artur Shehu, whom Albanian authorities and media have linked to organised crime and drug trafficking. Reporting cited by Raskin's letter has alleged that Shehu used falsified property documents and that local residents warned Kushner about questions surrounding his ownership of the land.

Albanian prosecutors have frozen assets connected with the transaction while investigating suspected fraud. Reuters reported in July that the businessman who sold the land was suspected of falsifying deeds. Kushner has said he was unaware of any fraudulent claim to ownership.

Raskin's letter also raises allegations that Kushner's private security personnel assaulted local residents who protested against the transaction. The allegation is based on media reports and has not resulted in a charge against Kushner or his company.

Flamingo protests

The proposed development has become a flashpoint for environmental and political protests in Albania.

Kushner and his family became interested in the Albanian coast while yachting in the Adriatic. His wife, Ivanka Trump, has described the discovery of the area, while the planned development has focused attention on Sazan Island and nearby protected coastal territory.

The protests have become known as the "Flamingo Revolution", a reference to migratory birds found along the Zvernec coastline.

The movement has already forced the Albanian government to reconsider elements of the project. Prime Minister Edi Rama's administration suspended the resort in June after European lawmakers warned that it could jeopardise Albania's European Union accession process. The government subsequently agreed in July to amend legislation governing protected areas, changes that critics said were linked to the project.

The protest movement takes its name from the migratory birds on the Zvernec coastline, and it has already forced a government retreat. Edi Rama's administration suspended the resort in June after EU lawmakers warned it put the accession process at risk, and agreed in July to amend the protected areas law the project had depended on.

The movement has since become an international cause. Dua Lipa, Albania's best-known export, backed the protests in July, and a pro-Palestinian flotilla arrived to support them on August 22. A Chatham House study in June read the demonstrations as a case of a problem common to developing countries - a government trading environmental protection for foreign political access.

Raskin's letter presents the Albanian government's actions in similar terms, suggesting that concessions to Kushner could have been influenced by his close relationship with Trump and his involvement in US foreign policy.

The controversy also echoes a separate Kushner-linked development in neighbouring Serbia, where Affinity Partners had secured a 99-year lease for the bomb-damaged former General Staff complex in central Belgrade.

The Serbian government had granted the lease free of charge for a planned hotel and residential development. The project required the site to lose its protected status and for its damaged buildings to be demolished.

The project collapsed after Serbian prosecutors indicted four officials over abuse of office and forgery in connection with the project, and within hours Kushner's firm dropped it. Serbian students had spent months protesting against it, at one point forming a living wall around the site. The two disputes differ in their legal and political circumstances, but both have raised questions about the advantages governments may offer to investors connected to the Trump family.

The pattern in both countries is the same: a government that wants something from Washington offers a Trump-family-linked investor terms no ordinary bidder would get, on a site the public considers its own, and the legal defect in the concession turns out to be the thing that kills the deal. IntelliNews’ survey of Trump-linked Balkan investments in April flagged the transparency problem.

In both cases, opponents have argued that valuable or historically significant public assets were being transferred on unusually favourable terms, while governments pursued closer political and economic ties with Washington.

Raskin's intervention gives the Albanian dispute a new US political dimension. As ranking member, he cannot compel Kushner to provide the documents he has requested without support from the committee majority. But his letter puts specific allegations, dates and documentary requests into the congressional record.