The daughter of Pakistan's prime minister, Nawaz Sharif, was involved in the Panama Papers scandal, a German newspaper said, as it backed up an earlier claim.

German daily Suddeutsche Zeitung on Monday posted documents on Twitter confirming that Maryam Safdar is the beneficial owner of offshore companies named in Panama Papers.

For those in #Pakistan who doubt the role of the prime ministers daughter Mariam Safdar in #panamapapers - some of the docs. Judge yourself. pic.twitter.com/DCd45aTxTK — SZ Investigativ (@SZ_Investigativ) January 23, 2017

Al Jazeera searched the database of the International Consortium of Investigative Journalists (ICIJ) that includes 11.5 million documents leaked from the Panama-based law firm Mossack Fonseca, and found Safdar's details.

Safdar was listed as the beneficiary of Nescoll Limited, an offshore company registered in British Virgin Islands. Her brother Hussain Nawaz Sharif was listed as the signatory.

In all, Sharif's daughter Maryam and sons Hasan and Hussain owned at least three off-shore holding companies registered in the British Virgin Islands, the leaked documents show.

According to the ICIJ, a non-profit group in the United States, these firms were involved in the purchase and mortgage of at least $13.8m in UK properties. One of the holding companies also bought shares in another, Liberia-based, company for $11.2m in August 2007, the documents show.

Owning off-shore companies is not illegal in Pakistan, but the Sharifs are being challenged on the source of the funds. Opposition politicians allege the funds were gained through corrupt practices during Sharif's previous two stints as prime minister in the 1990s.

Allegations of corruption against the Sharif family are being heard in Pakistan's Supreme Court.

Prime Minister Sharif told the court in a written submission last year that the leak was not the proof against him, as his children were not his dependents.

He said he was not holding any offshore companies. Sharif also claimed that he had paid tax and declared all of his assets in 2013.

The Panama Papers leak revealed how Mossack Fonseca allegedly helped current and former world leaders, as well as businessmen, criminals, celebrities and sports stars, evade or avoid tax via anonymously-owned shell companies and offshore accounts.

The story garnered wall-to-wall coverage and dominated front pages of newspapers across the world.

ICIJ coordinated the reporting, with 376 journalists from 109 news organisations and 76 countries poring over the files.