Panamanian police have raided the headquarters of Mossack Fonseca, the law firm at the center of a massive data leak known as “Panama Papers”.

Prosecutors said the operation had been carried out at the company’s offices in Panama City “without incident or interference”.

The leaked “Panama Papers” have shown how some wealthy people use offshore companies to evade tax and avoid sanctions.

Mossack Fonseca has denied wrongdoing. The company says it is the victim of a hack and that the information is being misrepresented.

Panama’s President Juan Carlos Varela has promised to work with other countries to improve transparency in its offshore financial industry.

Police carried out the raid along with officials from an organized crime unit. Officers set up a perimeter around the headquarters while prosecutors entered the offices to search for documents.

Afterwards, the attorney general’s office said the aim had been “to obtain documentation linked to the information published in news articles that establish the use of the firm in illicit activities”.

The statement added that searches would also take place at Mossack Fonseca’s subsidiaries.

Panama’s government promised an investigation soon after news reports emerged more than a week ago based on more than 11 million documents from the company.

Mossack Fonseca tweeted that it “continues to co-operate with authorities in investigations made at our headquarters”.

Many other countries are probing possible financial crimes by the rich and powerful in the aftermath of the leak.

The company partner Ramon Fonseca says it had been hacked by servers based abroad and has filed a complaint with the Panamanian attorney general’s office.

Ramon Fonseca served as a minister in Juan Carlos Valera’s government but stepped aside earlier this year after separate allegations linked Mossack Fonseca to the corruption scandal engulfing the Brazilian state oil company Petrobras.